From 820aac6c0b33f679045e5d0bcad13a801403caef Mon Sep 17 00:00:00 2001
From: RedYetiDev <38299977+RedYetiDev@users.noreply.github.com>
Date: Tue, 20 Aug 2024 18:07:24 -0400
Subject: [PATCH] test: update wpt

---
 .../cross-partition.tentative.https.html      | 397 +++++++++---
 .../wpt/FileAPI/blob/Blob-constructor.any.js  |  12 +-
 test/fixtures/wpt/README.md                   |  42 +-
 .../derive_bits_keys/cfrg_curves_bits.js      |  25 +-
 .../derived_bits_length.https.any.js          |  11 +
 .../derive_bits_keys/derived_bits_length.js   |  36 ++
 .../derived_bits_length_testcases.js          |  30 +
 .../derived_bits_length_vectors.js            |  33 +
 .../derive_bits_keys/ecdh_bits.js             |  19 -
 .../wpt/WebCryptoAPI/derive_bits_keys/hkdf.js |  19 -
 .../WebCryptoAPI/derive_bits_keys/pbkdf2.js   |  20 -
 .../wpt/WebCryptoAPI/getRandomValues.any.js   |  11 +
 .../importKey-unsettled-promise.https.any.js  |  17 +
 .../wpt/WebCryptoAPI/sign_verify/eddsa.js     | 591 +++++++-----------
 .../WebCryptoAPI/sign_verify/eddsa_vectors.js | 141 ++++-
 test/fixtures/wpt/common/META.yml             |   1 -
 .../wpt/common/dispatcher/dispatcher.js       |  29 +-
 test/fixtures/wpt/common/dummy.json           |   1 +
 test/fixtures/wpt/common/media.js             |  16 +-
 test/fixtures/wpt/common/top-layer.js         |  29 +
 ...ecompression-buffersource.tentative.any.js |  12 +-
 .../console-countReset-logging-manual.html    |   6 +-
 .../console/console-log-large-array.any.js    |   8 +
 .../wpt/console/console-log-symbol.any.js     |  10 +
 test/fixtures/wpt/dom/abort/WEB_FEATURES.yml  |   6 +
 .../wpt/dom/abort/abort-signal-any-crash.html |  23 +
 .../abort/resources/abort-signal-any-tests.js |  39 ++
 .../wpt/dom/events/Event-dispatch-click.html  |  56 ++
 .../Event-dispatch-on-disabled-elements.html  |   2 +-
 ...t-dispatch-single-activation-behavior.html | 164 +++++
 ...nt-dispatch-throwing-multiple-globals.html |  69 ++
 .../events/EventTarget-constructible.any.js   |  17 +
 .../fixtures/wpt/dom/events/event-global.html |  10 +
 .../events/pointer-event-document-move.html   |  29 +
 ...entDefault-during-activation-behavior.html |  53 ++
 .../wpt/dom/events/remove-all-listeners.html  |  95 +++
 .../wpt/dom/events/scrolling/WEB_FEATURES.yml |   4 +
 .../events/scrolling/overscroll-deltas.html   | 208 ++++--
 ...croll-event-fired-to-scrolled-element.html |  11 +-
 .../dom/events/scrolling/scroll_support.js    | 125 +++-
 ...d-after-sequence-of-scrolls.tentative.html |  76 ++-
 ...d-for-mandatory-snap-point-after-load.html |  87 +++
 ...d-event-fired-for-programmatic-scroll.html | 166 ++---
 ...nd-event-fired-for-scroll-attr-change.html | 147 +++++
 ...ollend-event-fired-for-scrollIntoView.html |   8 +-
 .../scrollend-event-fired-to-document.html    | 142 +++--
 ...d-to-element-with-overscroll-behavior.html | 233 ++++---
 ...llend-event-fired-to-scrolled-element.html |  68 --
 .../scrollend-event-fired-to-window.html      |  90 +--
 ...ollend-event-fires-on-visual-viewport.html |  68 ++
 ...end-event-fires-to-iframe-inner-frame.html |  30 +
 ...crollend-event-fires-to-iframe-window.html |  77 +++
 .../scrollend-event-for-user-scroll.html      | 149 +----
 ...crollend-event-not-fired-on-no-scroll.html | 114 ++++
 .../scrollend-fires-to-text-input.html        |  32 +
 .../scrolling/scrollend-user-scroll-common.js | 150 +++++
 ...ollend-with-snap-on-fractional-offset.html |  85 +++
 .../wheel-event-transactions-basic.html       | 140 +++++
 ...t-transactions-multiple-action-chains.html | 101 +++
 ...nt-transactions-target-display-change.html | 100 +++
 ...el-event-transactions-target-elements.html |  74 +++
 .../wheel-event-transactions-target-move.html |  85 +++
 ...eel-event-transactions-target-removal.html |  92 +++
 ...heel-event-transactions-target-resize.html |  97 +++
 .../wpt/hr-time/raf-coarsened-time.https.html |  36 ++
 .../raf-coarsened-time.https.html.headers     |   2 +
 ...cross-realm-callback-report-exception.html |  28 +
 .../structured-clone/WEB_FEATURES.yml         |   3 +
 ...ructured-clone-battery-of-tests-harness.js |   5 +-
 ...one-battery-of-tests-with-transferables.js | 147 +++++
 .../structured-clone-battery-of-tests.js      | 257 ++++++--
 .../structured-clone-cross-realm-method.html  |  20 +
 ...tructured-clone-detached-window-crash.html |  11 +
 .../structured-clone/structured-clone.any.js  |   7 +-
 .../timers/clearinterval-from-callback.any.js |  19 +
 .../timers/evil-spec-example.any.js           |  12 +
 .../webappapis/timers/evil-spec-example.html  |  23 -
 ...cross-realm-callback-report-exception.html |  32 +
 ...cross-realm-callback-report-exception.html |  28 +
 test/fixtures/wpt/interfaces/dom.idl          |  12 +-
 test/fixtures/wpt/interfaces/html.idl         |   2 -
 ...k-forward-cache-restoration.tentative.html |  95 +++
 .../droppedentriescount.any.js                |  81 +++
 .../idlharness-shadowrealm.window.js          |   2 +
 ...avigation-id-detached-frame.tentative.html |  30 +
 ...avigation-id-element-timing.tentative.html |  14 +
 .../navigation-id-initial-load.tentative.html |  49 ++
 ...-long-task-task-attribution.tentative.html |  14 +
 .../navigation-id-mark-measure.tentative.html |  14 +
 .../navigation-id-reset.tentative.html        |  53 ++
 ...vigation-id-resource-timing.tentative.html |  14 +
 .../navigation-id-worker-created-entries.html |  27 +
 .../navigation-id.helper.js                   | 144 +++++
 .../abort-block-bfcache.window.js             |  21 +
 ...tion-timing-attributes.tentative.window.js |  55 ++
 ...g-bfcache-reasons-stay.tentative.window.js |  47 ++
 ...igation-timing-bfcache.tentative.window.js |  28 +
 ...g-cross-origin-bfcache.tentative.window.js |  60 ++
 ...avigation-timing-fetch.tentative.window.js |  40 ++
 ...mes-without-attributes.tentative.window.js | 103 +++
 ...tion-timing-lock.https.tentative.window.js |  32 +
 ...ing-navigation-failure.tentative.window.js |  26 +
 ...on-timing-not-bfcached.tentative.window.js |  36 ++
 ...ng-redirect-on-history.tentative.window.js |  53 ++
 ...vigation-timing-reload.tentative.window.js |  50 ++
 ...ng-same-origin-bfcache.tentative.window.js |  61 ++
 ...ng-same-origin-replace.tentative.window.js |  43 ++
 .../not-restored-reasons/test-helper.js       |  57 ++
 .../resources/child-frame.html                |   7 +
 .../performance-timeline/resources/empty.html |   0
 .../resources/going-back.html                 |   9 +
 .../resources/include-frames-helper.js        |  60 ++
 .../resources/include-frames-subframe.html    |  43 ++
 .../resources/json_resource.json              |   4 +
 .../resources/make_long_task.js               |   4 +
 .../navigation-id-detached-frame-page.html    |  21 +
 .../resources/worker-navigation-id.js         |   6 +
 ...upportedEntryTypes-cross-realm-access.html |  18 +
 .../tentative/detached-frame.html             |  27 +
 .../tentative/include-frames-originA-A-A.html |  93 +++
 .../tentative/include-frames-originA-A.html   |  76 +++
 .../tentative/include-frames-originA-AA.html  |  51 ++
 .../tentative/include-frames-originA-AB.html  |  53 ++
 .../tentative/include-frames-originA-B-A.html |  91 +++
 .../tentative/include-frames-originA-B-B.html |  57 ++
 .../tentative/include-frames-originA-B.html   |  50 ++
 .../tentative/performance-entry-source.html   |  37 ++
 .../with-filter-options-originA.html          |  26 +
 .../timing-removed-iframe.html                |  16 +
 test/fixtures/wpt/resource-timing/META.yml    |   1 -
 .../body-size-cross-origin.https.html         |  63 ++
 .../resource-timing/content-type-parsing.html |  76 +++
 .../wpt/resource-timing/content-type.html     | 127 ++++
 ...-origin-start-end-time-with-redirects.html |  20 +-
 .../delivery-type.tentative.any.js            |  90 +++
 .../entries-for-network-errors.sub.https.html |  16 +
 .../fetch-cross-origin-redirect.https.html    |   2 +-
 .../resource-timing/iframe-failed-commit.html |  34 +-
 .../iframe-sequence-of-events.html            |  16 +-
 .../resource-timing/initiator-type/link.html  |  57 +-
 .../initiator-type/script.html                |   2 +
 .../resource-timing/initiator-type/video.html |   4 +-
 .../initiator-type/workers.html               |   2 +-
 .../interim-response-times.h2.html            |  74 +++
 .../interim-response-times.html               |  72 +++
 .../internal-resources-not-counted.html       |  39 ++
 .../nested-nav-fallback-timing.html           |  33 +
 ...s-origin-css-fetched-memory-cache.sub.html |  53 ++
 ...not-found-after-cross-origin-redirect.html |  25 +-
 .../queue-entry-regardless-buffer-size.html   |  38 ++
 ...ing-failed-fetch-web-bundle.tentative.html |  53 ++
 .../resource-timing-failed-fetch.html         |  34 +
 .../resource-timing/resource-timing-level1.js |  41 --
 .../resource-timing/resources/child_script.js |   1 +
 .../resource-timing/resources/delay-load.html |   4 +
 .../resources/entry-invariants.js             |  43 +-
 .../resource-timing/resources/frame-timing.js |  97 +--
 .../resources/get-resourceID.js               |  30 +
 .../resources/loadingResources.js             |  21 +
 .../resources/nested-contexts.js              |  37 +-
 ...n-css-fetched-memory-cache-iframe.sub.html |   8 +
 .../resources/parent_script.js                |   1 +
 .../resources/resource-loaders.js             |  77 ++-
 .../resources/test-initiator.js               |  16 +
 .../resource-timing/response-status-code.html | 165 +++++
 .../resource-timing/sizes-redirect-img.html   |   8 +-
 .../tentative/document-initiated.html         |  78 +++
 .../tentative/script-initiated.html           |  24 +
 .../tentative/stylesheet-initiated.html       |  23 +
 test/fixtures/wpt/resource-timing/tojson.html |   4 +-
 .../fixtures/wpt/resources/check-layout-th.js |   3 +-
 .../declarative-shadow-dom-polyfill.js        |  25 -
 test/fixtures/wpt/resources/idlharness.js     |   1 +
 test/fixtures/wpt/resources/testdriver.js     | 222 ++++++-
 test/fixtures/wpt/resources/testharness.js    | 194 +++---
 .../wpt/resources/testharnessreport.js        |  25 -
 .../transfer-with-messageport.window.js       |  12 +-
 test/fixtures/wpt/url/META.yml                |   1 -
 test/fixtures/wpt/url/README.md               |  12 +-
 .../wpt/url/a-element-origin-xhtml.xhtml      |   6 +-
 test/fixtures/wpt/url/a-element-origin.html   |   6 +-
 test/fixtures/wpt/url/a-element-xhtml.xhtml   |   6 +-
 test/fixtures/wpt/url/a-element.html          |   6 +-
 test/fixtures/wpt/url/failure.html            |   5 +-
 .../wpt/url/resources/a-element-origin.js     |   5 +-
 test/fixtures/wpt/url/resources/a-element.js  |   5 +-
 .../urltestdata-javascript-only.json          |  18 +
 .../wpt/url/resources/urltestdata.json        |  15 -
 test/fixtures/wpt/url/url-constructor.any.js  |   5 +-
 test/fixtures/wpt/url/url-origin.any.js       |   5 +-
 test/fixtures/wpt/versions.json               |  42 +-
 test/fixtures/wpt/wasm/jsapi/assertions.js    |   5 +
 test/fixtures/wpt/wasm/jsapi/bad-imports.js   |   1 +
 .../wpt/wasm/jsapi/constructor/compile.any.js |   2 +-
 .../instantiate-bad-imports.any.js            |   2 +-
 .../wasm/jsapi/constructor/instantiate.any.js |   2 +-
 .../wasm/jsapi/constructor/multi-value.any.js |   2 +-
 .../wasm/jsapi/constructor/toStringTag.any.js |   2 +-
 .../wasm/jsapi/constructor/validate.any.js    |   2 +-
 .../jsapi/exception/basic.tentative.any.js    |  11 +-
 .../exception/constructor.tentative.any.js    |   2 +-
 .../jsapi/exception/getArg.tentative.any.js   |   2 +-
 .../jsapi/exception/identity.tentative.any.js |   2 +-
 .../wasm/jsapi/exception/is.tentative.any.js  |   2 +-
 .../jsapi/exception/toString.tentative.any.js |   2 +-
 .../wasm/jsapi/function/call.tentative.any.js |   2 +-
 .../function/constructor.tentative.any.js     |   2 +-
 .../jsapi/function/table.tentative.any.js     |   2 +-
 .../wasm/jsapi/function/type.tentative.any.js |   2 +-
 .../wpt/wasm/jsapi/gc/casts.tentative.any.js  | 332 ++++++++++
 .../jsapi/gc/exported-object.tentative.any.js | 190 ++++++
 .../wpt/wasm/jsapi/gc/i31.tentative.any.js    |  98 +++
 .../wpt/wasm/jsapi/global/constructor.any.js  |   2 +-
 .../wpt/wasm/jsapi/global/toString.any.js     |   2 +-
 .../wasm/jsapi/global/type.tentative.any.js   |   2 +-
 .../wasm/jsapi/global/value-get-set.any.js    |   2 +-
 .../wpt/wasm/jsapi/global/valueOf.any.js      |   2 +-
 .../instance/constructor-bad-imports.any.js   |   2 +-
 .../jsapi/instance/constructor-caching.any.js |   2 +-
 .../wasm/jsapi/instance/constructor.any.js    |   2 +-
 .../wpt/wasm/jsapi/instance/exports.any.js    |   2 +-
 .../wpt/wasm/jsapi/instance/toString.any.js   |   2 +-
 .../wpt/wasm/jsapi/instanceTestFactory.js     |   8 +-
 test/fixtures/wpt/wasm/jsapi/interface.any.js |   2 +-
 .../constructor-shared.tentative.any.js       |   2 +-
 .../memory/constructor-types.tentative.any.js |   4 +-
 .../wpt/wasm/jsapi/memory/constructor.any.js  |   2 +-
 .../wpt/wasm/jsapi/memory/grow.any.js         |   2 +-
 .../wasm/jsapi/memory/type.tentative.any.js   |   4 +-
 .../wpt/wasm/jsapi/module/constructor.any.js  |   2 +-
 .../wasm/jsapi/module/customSections.any.js   |   2 +-
 .../wpt/wasm/jsapi/module/exports.any.js      |   8 +-
 .../wpt/wasm/jsapi/module/imports.any.js      |   2 +-
 .../module/moduleSource.tentative.any.js      |  35 ++
 .../wpt/wasm/jsapi/module/toString.any.js     |   2 +-
 .../fixtures/wpt/wasm/jsapi/prototypes.any.js |   2 +-
 .../table/constructor-types.tentative.any.js  |   4 +-
 .../wpt/wasm/jsapi/table/constructor.any.js   |   2 +-
 .../wpt/wasm/jsapi/table/get-set.any.js       |   2 +-
 .../fixtures/wpt/wasm/jsapi/table/grow.any.js |   2 +-
 .../wpt/wasm/jsapi/table/length.any.js        |   2 +-
 .../wpt/wasm/jsapi/table/toString.any.js      |   2 +-
 .../wasm/jsapi/table/type.tentative.any.js    |   2 +-
 .../jsapi/tag/constructor.tentative.any.js    |   2 +-
 .../wasm/jsapi/tag/toString.tentative.any.js  |   2 +-
 .../wpt/wasm/jsapi/tag/type.tentative.any.js  |   2 +-
 .../wpt/wasm/jsapi/wasm-module-builder.js     | 352 ++++++++---
 .../resources/worker-source-phase.js          |  10 +
 .../esm-integration/resources/worker.js       |   3 +-
 .../script-src-allows-wasm.tentative.html     |  21 +
 .../script-src-blocks-wasm.tentative.sub.html |  21 +
 .../source-phase.tentative.html               |  35 ++
 .../worker-import-source-phase.tentative.html |  13 +
 .../esm-integration/worker.tentative.html     |   3 +
 .../broadcastchannel/WEB_FEATURES.yml         |   3 +
 .../broadcastchannel/basics.any.js            |   8 +
 ...P-iframe-opens-3P-window.partitioned.html} |   0
 ...> localstorage-basic-partitioned.sub.html} |   2 +-
 ...orage-cross-origin-iframe.https.window.js} |   0
 ...sessionStorage-basic-partitioned.sub.html} |   2 +-
 260 files changed, 9166 insertions(+), 1801 deletions(-)
 create mode 100644 test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length.https.any.js
 create mode 100644 test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length.js
 create mode 100644 test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length_testcases.js
 create mode 100644 test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length_vectors.js
 create mode 100644 test/fixtures/wpt/WebCryptoAPI/import_export/crashtests/importKey-unsettled-promise.https.any.js
 create mode 100644 test/fixtures/wpt/common/dummy.json
 create mode 100644 test/fixtures/wpt/common/top-layer.js
 create mode 100644 test/fixtures/wpt/console/console-log-large-array.any.js
 create mode 100644 test/fixtures/wpt/console/console-log-symbol.any.js
 create mode 100644 test/fixtures/wpt/dom/abort/WEB_FEATURES.yml
 create mode 100644 test/fixtures/wpt/dom/abort/abort-signal-any-crash.html
 create mode 100644 test/fixtures/wpt/dom/events/Event-dispatch-single-activation-behavior.html
 create mode 100644 test/fixtures/wpt/dom/events/Event-dispatch-throwing-multiple-globals.html
 create mode 100644 test/fixtures/wpt/dom/events/pointer-event-document-move.html
 create mode 100644 test/fixtures/wpt/dom/events/preventDefault-during-activation-behavior.html
 create mode 100644 test/fixtures/wpt/dom/events/remove-all-listeners.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/WEB_FEATURES.yml
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-mandatory-snap-point-after-load.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-scroll-attr-change.html
 delete mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-scrolled-element.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-on-visual-viewport.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-to-iframe-inner-frame.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-to-iframe-window.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-event-not-fired-on-no-scroll.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-fires-to-text-input.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-user-scroll-common.js
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/scrollend-with-snap-on-fractional-offset.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-basic.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-multiple-action-chains.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-display-change.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-elements.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-move.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-removal.html
 create mode 100644 test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-resize.html
 create mode 100644 test/fixtures/wpt/hr-time/raf-coarsened-time.https.html
 create mode 100644 test/fixtures/wpt/hr-time/raf-coarsened-time.https.html.headers
 create mode 100644 test/fixtures/wpt/html/webappapis/microtask-queuing/queue-microtask-cross-realm-callback-report-exception.html
 create mode 100644 test/fixtures/wpt/html/webappapis/structured-clone/WEB_FEATURES.yml
 create mode 100644 test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-cross-realm-method.html
 create mode 100644 test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-detached-window-crash.html
 create mode 100644 test/fixtures/wpt/html/webappapis/timers/clearinterval-from-callback.any.js
 create mode 100644 test/fixtures/wpt/html/webappapis/timers/evil-spec-example.any.js
 delete mode 100644 test/fixtures/wpt/html/webappapis/timers/evil-spec-example.html
 create mode 100644 test/fixtures/wpt/html/webappapis/timers/setinterval-cross-realm-callback-report-exception.html
 create mode 100644 test/fixtures/wpt/html/webappapis/timers/settimeout-cross-realm-callback-report-exception.html
 create mode 100644 test/fixtures/wpt/performance-timeline/back-forward-cache-restoration.tentative.html
 create mode 100644 test/fixtures/wpt/performance-timeline/droppedentriescount.any.js
 create mode 100644 test/fixtures/wpt/performance-timeline/idlharness-shadowrealm.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id-detached-frame.tentative.html
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id-element-timing.tentative.html
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id-initial-load.tentative.html
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id-long-task-task-attribution.tentative.html
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id-mark-measure.tentative.html
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id-reset.tentative.html
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id-resource-timing.tentative.html
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id-worker-created-entries.html
 create mode 100644 test/fixtures/wpt/performance-timeline/navigation-id.helper.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/abort-block-bfcache.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-attributes.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-bfcache-reasons-stay.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-bfcache.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-cross-origin-bfcache.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-fetch.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-iframes-without-attributes.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-lock.https.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-navigation-failure.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-not-bfcached.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-redirect-on-history.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-reload.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-same-origin-bfcache.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-same-origin-replace.tentative.window.js
 create mode 100644 test/fixtures/wpt/performance-timeline/not-restored-reasons/test-helper.js
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/child-frame.html
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/empty.html
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/going-back.html
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/include-frames-helper.js
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/include-frames-subframe.html
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/json_resource.json
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/make_long_task.js
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/navigation-id-detached-frame-page.html
 create mode 100644 test/fixtures/wpt/performance-timeline/resources/worker-navigation-id.js
 create mode 100644 test/fixtures/wpt/performance-timeline/supportedEntryTypes-cross-realm-access.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/detached-frame.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-A-A.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-A.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-AA.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-AB.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B-A.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B-B.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/performance-entry-source.html
 create mode 100644 test/fixtures/wpt/performance-timeline/tentative/with-filter-options-originA.html
 create mode 100644 test/fixtures/wpt/performance-timeline/timing-removed-iframe.html
 create mode 100644 test/fixtures/wpt/resource-timing/body-size-cross-origin.https.html
 create mode 100644 test/fixtures/wpt/resource-timing/content-type-parsing.html
 create mode 100644 test/fixtures/wpt/resource-timing/content-type.html
 create mode 100644 test/fixtures/wpt/resource-timing/delivery-type.tentative.any.js
 create mode 100644 test/fixtures/wpt/resource-timing/interim-response-times.h2.html
 create mode 100644 test/fixtures/wpt/resource-timing/interim-response-times.html
 create mode 100644 test/fixtures/wpt/resource-timing/internal-resources-not-counted.html
 create mode 100644 test/fixtures/wpt/resource-timing/nested-nav-fallback-timing.html
 create mode 100644 test/fixtures/wpt/resource-timing/no-entries-for-cross-origin-css-fetched-memory-cache.sub.html
 create mode 100644 test/fixtures/wpt/resource-timing/queue-entry-regardless-buffer-size.html
 create mode 100644 test/fixtures/wpt/resource-timing/resource-timing-failed-fetch-web-bundle.tentative.html
 create mode 100644 test/fixtures/wpt/resource-timing/resource-timing-failed-fetch.html
 create mode 100644 test/fixtures/wpt/resource-timing/resources/child_script.js
 create mode 100644 test/fixtures/wpt/resource-timing/resources/delay-load.html
 create mode 100644 test/fixtures/wpt/resource-timing/resources/get-resourceID.js
 create mode 100644 test/fixtures/wpt/resource-timing/resources/loadingResources.js
 create mode 100644 test/fixtures/wpt/resource-timing/resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html
 create mode 100644 test/fixtures/wpt/resource-timing/resources/parent_script.js
 create mode 100644 test/fixtures/wpt/resource-timing/resources/test-initiator.js
 create mode 100644 test/fixtures/wpt/resource-timing/response-status-code.html
 create mode 100644 test/fixtures/wpt/resource-timing/tentative/document-initiated.html
 create mode 100644 test/fixtures/wpt/resource-timing/tentative/script-initiated.html
 create mode 100644 test/fixtures/wpt/resource-timing/tentative/stylesheet-initiated.html
 delete mode 100644 test/fixtures/wpt/resources/declarative-shadow-dom-polyfill.js
 create mode 100644 test/fixtures/wpt/url/resources/urltestdata-javascript-only.json
 create mode 100644 test/fixtures/wpt/wasm/jsapi/gc/casts.tentative.any.js
 create mode 100644 test/fixtures/wpt/wasm/jsapi/gc/exported-object.tentative.any.js
 create mode 100644 test/fixtures/wpt/wasm/jsapi/gc/i31.tentative.any.js
 create mode 100644 test/fixtures/wpt/wasm/jsapi/module/moduleSource.tentative.any.js
 create mode 100644 test/fixtures/wpt/wasm/webapi/esm-integration/resources/worker-source-phase.js
 create mode 100644 test/fixtures/wpt/wasm/webapi/esm-integration/script-src-allows-wasm.tentative.html
 create mode 100644 test/fixtures/wpt/wasm/webapi/esm-integration/script-src-blocks-wasm.tentative.sub.html
 create mode 100644 test/fixtures/wpt/wasm/webapi/esm-integration/source-phase.tentative.html
 create mode 100644 test/fixtures/wpt/wasm/webapi/esm-integration/worker-import-source-phase.tentative.html
 create mode 100644 test/fixtures/wpt/webmessaging/broadcastchannel/WEB_FEATURES.yml
 rename test/fixtures/wpt/webstorage/{localstorage-about-blank-3P-iframe-opens-3P-window.partitioned.tentative.html => localstorage-about-blank-3P-iframe-opens-3P-window.partitioned.html} (100%)
 rename test/fixtures/wpt/webstorage/{localstorage-basic-partitioned.tentative.sub.html => localstorage-basic-partitioned.sub.html} (97%)
 rename test/fixtures/wpt/webstorage/{localstorage-cross-origin-iframe.tentative.https.window.js => localstorage-cross-origin-iframe.https.window.js} (100%)
 rename test/fixtures/wpt/webstorage/{sessionStorage-basic-partitioned.tentative.sub.html => sessionStorage-basic-partitioned.sub.html} (97%)

diff --git a/test/fixtures/wpt/FileAPI/BlobURL/cross-partition.tentative.https.html b/test/fixtures/wpt/FileAPI/BlobURL/cross-partition.tentative.https.html
index c75ce07d054eb79..11d9787b8873a8b 100644
--- a/test/fixtures/wpt/FileAPI/BlobURL/cross-partition.tentative.https.html
+++ b/test/fixtures/wpt/FileAPI/BlobURL/cross-partition.tentative.https.html
@@ -13,31 +13,54 @@
 <body>
 <script>
 
-const did_revoke_response = "URL.revokeObjectURL did revoke";
-const did_not_revoke_response = "URL.revokeObjectURL did not revoke";
+const fetch_unsuccessful_response = "Fetch failed";
+const fetch_successful_response = "Fetch succeeded";
+const js_finished = "revoking blob_url js finished";
+
+// Fetches a previously revoked blob_url to see if the revoking was successful.
+async function fetch_contents_check(blob_url) {
+  try {
+    const blob = await fetch(blob_url).then(response => response.blob());
+    await blob.text();
+  } catch(e) {
+    return fetch_unsuccessful_response;
+  }
+  return fetch_successful_response;
+}
 
 const can_blob_url_be_revoked_js = (blob_url, response_queue_name) => `
   async function test() {
     if (!('revokeObjectURL' in URL)) {
       return send("${response_queue_name}", "URL.revokeObjectURL is not exposed");
     }
-    try {
-      var blob = await fetch("${blob_url}").then(response => response.blob());
-      await blob.text();
-    } catch {
-      return send("${response_queue_name}", "Blob URL invalid");
-    }
     try {
       URL.revokeObjectURL("${blob_url}");
     } catch(e) {
       return send("${response_queue_name}", e.toString());
     }
+
+    // Create, fetch, and revoke a separate blob URL to better ensure that the
+    // revoke call above has had time to take effect before we return.
+    const blob_1 = new Blob(["blob data"], {type : "text/plain"});
+    const blob_url_1 = URL.createObjectURL(blob_1);
+    await fetch(blob_url_1).then(response => response.blob());
+    URL.revokeObjectURL(blob_url_1);
+
+    return send("${response_queue_name}", "${js_finished}");
+  }
+  await test();
+`;
+
+const can_blob_url_be_fetched_js = (blob_url, response_queue_name) => `
+  async function test() {
     try {
       const blob = await fetch("${blob_url}").then(response => response.blob());
+      await blob.text();
     } catch(e) {
-      return send("${response_queue_name}", "${did_revoke_response}");
+      return send("${response_queue_name}", "${fetch_unsuccessful_response}");
     }
-    return send("${response_queue_name}", "${did_not_revoke_response}");
+
+    return send("${response_queue_name}", "${fetch_successful_response}");
   }
   await test();
 `;
@@ -55,6 +78,9 @@
 const cross_site_origin = get_host_info().HTTPS_NOTSAMESITE_ORIGIN;
 
 async function create_test_iframes(t, response_queue_uuid) {
+  assert_equals("https://" + window.location.host, same_site_origin,
+  "this test assumes that the page's window.location.host corresponds to " +
+  "get_host_info().HTTPS_ORIGIN");
 
   // Create a same-origin iframe in a cross-site popup.
   const not_same_site_popup_uuid = newPopup(t, cross_site_origin);
@@ -71,30 +97,47 @@
   return [iframe_1_uuid, iframe_2_uuid];
 }
 
+// Tests revoking blob URL for same and cross partition iframes.
 promise_test(t => {
   return new Promise(async (resolve, reject) => {
     try {
+      // Creates blob URL.
+      const blob = new Blob(["blob data"], {type : "text/plain"});
+      const blob_url = window.URL.createObjectURL(blob);
+
+      // Fetches blob URL to ensure that it's valid.
+      const blob_fetch = await fetch_contents_check(blob_url);
+      if (blob_fetch !== fetch_successful_response) {
+        reject("Blob URL invalid");
+      }
+
+      // Creates same and cross partition iframes.
       const response_queue_uuid = token();
 
       const [iframe_1_uuid, iframe_2_uuid] =
         await create_test_iframes(t, response_queue_uuid);
 
-      const blob = new Blob(["blob data"], {type : "text/plain"});
-      const blob_url = window.URL.createObjectURL(blob);
-      t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
-
-      await send(iframe_1_uuid,
-           can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
-      var response = await receive(response_queue_uuid);
-      if (response !== did_not_revoke_response) {
-        reject(`Blob URL was revoked in not-same-top-level-site iframe: ${response}`);
+      // Attempt to revoke blob URL in cross partition iframe.
+      await send(iframe_1_uuid, can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
+      var response_1 = await receive(response_queue_uuid);
+      if (response_1 !== js_finished) {
+        reject(response_1);
+      }
+      response_1 = await fetch_contents_check(blob_url);
+      if (response_1 !== fetch_successful_response) {
+        reject(`Blob URL was revoked in not-same-top-level-site iframe: ${response_1}`);
       }
 
-      await send(iframe_2_uuid,
-           can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
-      response = await receive(response_queue_uuid);
-      if (response !== did_revoke_response) {
-        reject(`Blob URL wasn't revoked in same-top-level-site iframe: ${response}`);
+      // Attempt to revoke blob URL in same partition iframe.
+      await send(iframe_2_uuid, can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
+      var response_2 = await receive(response_queue_uuid);
+      if (response_2 !== js_finished) {
+        reject(response_2);
+      }
+      response_2 = await fetch_contents_check(blob_url);
+      if (response_2 !== fetch_unsuccessful_response) {
+        t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
+        reject(`Blob URL wasn't revoked in same-top-level-site iframe: ${response_2}`);
       }
 
       resolve();
@@ -111,48 +154,53 @@
   return worker_token;
 }
 
+const create_dedicated_worker_js = (origin, response_queue_uuid) => `
+  const importScript = ${importScript};
+  await importScript("/html/cross-origin-embedder-policy/credentialless" +
+                    "/resources/common.js");
+  await importScript("/html/anonymous-iframe/resources/common.js");
+  await importScript("/common/utils.js");
+  const newWorker = ${newWorker};
+  await send("${response_queue_uuid}", newWorker("${origin}"));
+`;
+
+// Tests revoking blob URL from same and cross partition dedicated worker.
 promise_test(t => {
   return new Promise(async (resolve, reject) => {
     try {
       const response_queue_uuid = token();
 
-      const create_worker_js = (origin) => `
-        const importScript = ${importScript};
-        await importScript("/html/cross-origin-embedder-policy/credentialless" +
-                         "/resources/common.js");
-        await importScript("/html/anonymous-iframe/resources/common.js");
-        await importScript("/common/utils.js");
-        const newWorker = ${newWorker};
-        await send("${response_queue_uuid}", newWorker("${origin}"));
-      `;
-
       const [iframe_1_uuid, iframe_2_uuid] =
         await create_test_iframes(t, response_queue_uuid);
 
-      // Create a dedicated worker in the cross-top-level-site iframe.
-      await send(iframe_1_uuid, create_worker_js(same_site_origin));
+      await send(iframe_1_uuid, create_dedicated_worker_js(same_site_origin, response_queue_uuid));
       const worker_1_uuid = await receive(response_queue_uuid);
 
-      // Create a dedicated worker in the same-top-level-site iframe.
-      await send(iframe_2_uuid, create_worker_js(same_site_origin));
+      await send(iframe_2_uuid, create_dedicated_worker_js(same_site_origin, response_queue_uuid));
       const worker_2_uuid = await receive(response_queue_uuid);
 
       const blob = new Blob(["blob data"], {type : "text/plain"});
       const blob_url = window.URL.createObjectURL(blob);
-      t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
 
-      await send(worker_1_uuid,
-           can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
-      var response = await receive(response_queue_uuid);
-      if (response !== did_not_revoke_response) {
-        reject(`Blob URL was revoked in not-same-top-level-site dedicated worker: ${response}`);
+      await send(worker_1_uuid, can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
+      var response_1 = await receive(response_queue_uuid);
+      if (response_1 !== js_finished) {
+        reject(response_1);
+      }
+      response_1 = await fetch_contents_check(blob_url);
+      if (response_1 !== fetch_successful_response) {
+        reject(`Blob URL was revoked in not-same-top-level-site dedicated worker: ${response_1}`);
       }
 
-      await send(worker_2_uuid,
-           can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
-      response = await receive(response_queue_uuid);
-      if (response !== did_revoke_response) {
-        reject(`Blob URL wasn't revoked in same-top-level-site dedicated worker: ${response}`);
+      await send(worker_2_uuid, can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
+      var response_2 = await receive(response_queue_uuid);
+      if (response_2 !== js_finished) {
+        reject(response_2);
+      }
+      response_2 = await fetch_contents_check(blob_url);
+      if (response_2 !== fetch_unsuccessful_response) {
+        t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
+        reject(`Blob URL wasn't revoked in same-top-level-site dedicated worker: ${response_2}`);
       }
 
       resolve();
@@ -169,48 +217,55 @@
   return worker_token;
 }
 
+const create_shared_worker_js = (origin, response_queue_uuid) => `
+  const importScript = ${importScript};
+  await importScript("/html/cross-origin-embedder-policy/credentialless" +
+                    "/resources/common.js");
+  await importScript("/html/anonymous-iframe/resources/common.js");
+  await importScript("/common/utils.js");
+  const newSharedWorker = ${newSharedWorker};
+  await send("${response_queue_uuid}", newSharedWorker("${origin}"));
+`;
+
+// Tests revoking blob URL from same and cross partition shared worker.
 promise_test(t => {
   return new Promise(async (resolve, reject) => {
     try {
       const response_queue_uuid = token();
 
-      const create_worker_js = (origin) => `
-        const importScript = ${importScript};
-        await importScript("/html/cross-origin-embedder-policy/credentialless" +
-                         "/resources/common.js");
-        await importScript("/html/anonymous-iframe/resources/common.js");
-        await importScript("/common/utils.js");
-        const newSharedWorker = ${newSharedWorker};
-        await send("${response_queue_uuid}", newSharedWorker("${origin}"));
-      `;
-
       const [iframe_1_uuid, iframe_2_uuid] =
         await create_test_iframes(t, response_queue_uuid);
 
       // Create a shared worker in the cross-top-level-site iframe.
-      await send(iframe_1_uuid, create_worker_js(same_site_origin));
+      await send(iframe_1_uuid, create_shared_worker_js(same_site_origin, response_queue_uuid));
       const worker_1_uuid = await receive(response_queue_uuid);
 
       // Create a shared worker in the same-top-level-site iframe.
-      await send(iframe_2_uuid, create_worker_js(same_site_origin));
+      await send(iframe_2_uuid, create_shared_worker_js(same_site_origin, response_queue_uuid));
       const worker_2_uuid = await receive(response_queue_uuid);
 
       const blob = new Blob(["blob data"], {type : "text/plain"});
       const blob_url = window.URL.createObjectURL(blob);
-      t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
 
-      await send(worker_1_uuid,
-           can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
-      var response = await receive(response_queue_uuid);
-      if (response !== did_not_revoke_response) {
-        reject(`Blob URL was revoked in not-same-top-level-site shared worker: ${response}`);
+      await send(worker_1_uuid, can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
+      var response_1 = await receive(response_queue_uuid);
+      if (response_1 !== js_finished) {
+        reject(response_1);
+      }
+      response_1 = await fetch_contents_check(blob_url);
+      if (response_1 !== fetch_successful_response) {
+        reject(`Blob URL was revoked in not-same-top-level-site shared worker: ${response_1}`);
       }
 
-      await send(worker_2_uuid,
-           can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
-      response = await receive(response_queue_uuid);
-      if (response !== did_revoke_response) {
-        reject(`Blob URL wasn't revoked in same-top-level-site shared worker: ${response}`);
+      await send(worker_2_uuid, can_blob_url_be_revoked_js(blob_url, response_queue_uuid));
+      var response_2 = await receive(response_queue_uuid);
+      if (response_2 !== js_finished) {
+        reject(response_2);
+      }
+      response_2 = await fetch_contents_check(blob_url);
+      if (response_2 !== fetch_unsuccessful_response) {
+        t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
+        reject(`Blob URL wasn't revoked in same-top-level-site shared worker: ${response_2}`);
       }
 
       resolve();
@@ -232,26 +287,27 @@
   return worker_token;
 }
 
+const create_service_worker_js = (origin, response_queue_uuid) => `
+  const importScript = ${importScript};
+  await importScript("/html/cross-origin-embedder-policy/credentialless" +
+                    "/resources/common.js");
+  await importScript("/html/anonymous-iframe/resources/common.js");
+  await importScript("/common/utils.js");
+  const newServiceWorker = ${newServiceWorker};
+  await send("${response_queue_uuid}", await newServiceWorker("${origin}"));
+`;
+
+// Tests revoking blob URL from a service worker.
 promise_test(t => {
   return new Promise(async (resolve, reject) => {
     try {
       const response_queue_uuid = token();
 
-      const create_worker_js = (origin) => `
-        const importScript = ${importScript};
-        await importScript("/html/cross-origin-embedder-policy/credentialless" +
-                         "/resources/common.js");
-        await importScript("/html/anonymous-iframe/resources/common.js");
-        await importScript("/common/utils.js");
-        const newServiceWorker = ${newServiceWorker};
-        await send("${response_queue_uuid}", await newServiceWorker("${origin}"));
-      `;
-
       const [iframe_1_uuid, iframe_2_uuid] =
         await create_test_iframes(t, response_queue_uuid);
 
       // Create a service worker in either iframe.
-      await send(iframe_1_uuid, create_worker_js(same_site_origin));
+      await send(iframe_1_uuid, create_service_worker_js(same_site_origin, response_queue_uuid));
       var worker_1_uuid = await receive(response_queue_uuid);
       t.add_cleanup(() =>
         send(worker_1_uuid, "self.registration.unregister();"));
@@ -272,5 +328,178 @@
     }
   });
 }, "Blob URL shouldn't be revocable from a service worker");
+
+// Tests fetching blob URL for same and cross partition iframes.
+promise_test(t => {
+  return new Promise(async (resolve, reject) => {
+    try {
+      // Creates blob URL.
+      const blob = new Blob(["blob data"], {type : "text/plain"});
+      const blob_url = window.URL.createObjectURL(blob);
+      t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
+
+      // Fetches blob URL to ensure that it's valid.
+      const blob_fetch = await fetch_contents_check(blob_url);
+      if (blob_fetch !== fetch_successful_response) {
+        reject("Blob URL invalid");
+      }
+
+      // Creates same and cross partition iframes.
+      const response_queue_uuid = token();
+
+      const [iframe_1_uuid, iframe_2_uuid] =
+        await create_test_iframes(t, response_queue_uuid);
+
+      // Attempt to fetch blob URL in cross partition iframe.
+      await send(iframe_1_uuid, can_blob_url_be_fetched_js(blob_url, response_queue_uuid));
+      var response_1 = await receive(response_queue_uuid);
+      if (response_1 !== fetch_unsuccessful_response) {
+        reject(`Blob URL was fetched in not-same-top-level-site iframe: ${response_1}`);
+      }
+
+      // Attempt to fetch blob URL in same partition iframe.
+      await send(iframe_2_uuid, can_blob_url_be_fetched_js(blob_url, response_queue_uuid));
+      var response_2 = await receive(response_queue_uuid);
+      if (response_2 !== fetch_successful_response) {
+        reject(`Blob URL wasn't fetched in same-top-level-site iframe: ${response_2}`);
+      }
+
+      resolve();
+    } catch (e) {
+      reject(e);
+    }
+  });
+}, "Blob URL shouldn't be fetched from a cross-partition iframe");
+
+// Tests fetching blob URL from same and cross partition dedicated worker.
+promise_test(t => {
+  return new Promise(async (resolve, reject) => {
+    try {
+      const response_queue_uuid = token();
+
+      // Creates same and cross partition iframes.
+      const [iframe_1_uuid, iframe_2_uuid] =
+        await create_test_iframes(t, response_queue_uuid);
+
+      // Creates a dedicated worker in the cross-top-level-site iframe.
+      await send(iframe_1_uuid, create_dedicated_worker_js(same_site_origin, response_queue_uuid));
+      const worker_1_uuid = await receive(response_queue_uuid);
+
+      // Creates a dedicated worker in the same-top-level-site iframe.
+      await send(iframe_2_uuid, create_dedicated_worker_js(same_site_origin, response_queue_uuid));
+      const worker_2_uuid = await receive(response_queue_uuid);
+
+      const blob = new Blob(["blob data"], {type : "text/plain"});
+      const blob_url = window.URL.createObjectURL(blob);
+      t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
+
+      // Attempts to fetch in the cross-top-level-site dedicated worker.
+      await send(worker_1_uuid, can_blob_url_be_fetched_js(blob_url, response_queue_uuid));
+      var response_1 = await receive(response_queue_uuid);
+      if (response_1 !== fetch_unsuccessful_response) {
+        reject(`Blob URL was fetched in not-same-top-level-site dedicated worker: ${response_1}`);
+      }
+
+      // Attempts to fetch in the same-top-level-site dedicated worker.
+      await send(worker_2_uuid, can_blob_url_be_fetched_js(blob_url, response_queue_uuid));
+      var response_2 = await receive(response_queue_uuid);
+      if (response_2 !== fetch_successful_response) {
+        reject(`Blob URL wasn't fetched in same-top-level-site dedicated worker: ${response_2}`);
+      }
+
+      resolve();
+    } catch (e) {
+      reject(e);
+    }
+  });
+}, "Blob URL shouldn't be fetched from a cross-partition dedicated worker");
+
+// Tests fetching blob URL from same and cross partition shared worker.
+promise_test(t => {
+  return new Promise(async (resolve, reject) => {
+    try {
+      const response_queue_uuid = token();
+
+      const [iframe_1_uuid, iframe_2_uuid] =
+        await create_test_iframes(t, response_queue_uuid);
+
+      // Create a shared worker in the cross-top-level-site iframe.
+      await send(iframe_1_uuid, create_shared_worker_js(same_site_origin, response_queue_uuid));
+      const worker_1_uuid = await receive(response_queue_uuid);
+
+      // Create a shared worker in the same-top-level-site iframe.
+      await send(iframe_2_uuid, create_shared_worker_js(same_site_origin, response_queue_uuid));
+      const worker_2_uuid = await receive(response_queue_uuid);
+
+      const blob = new Blob(["blob data"], {type : "text/plain"});
+      const blob_url = window.URL.createObjectURL(blob);
+      t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
+
+      // Attempts to fetch in the cross-top-level-site shared worker.
+      await send(worker_1_uuid, can_blob_url_be_fetched_js(blob_url, response_queue_uuid));
+      var response_1 = await receive(response_queue_uuid);
+      if (response_1 !== fetch_unsuccessful_response) {
+        reject(`Blob URL was fetched in not-same-top-level-site shared worker: ${response_1}`);
+      }
+
+      // Attempts to fetch in the same-top-level-site shared worker.
+      await send(worker_2_uuid, can_blob_url_be_fetched_js(blob_url, response_queue_uuid));
+      var response_2 = await receive(response_queue_uuid);
+      if (response_2 !== fetch_successful_response) {
+        reject(`Blob URL wasn't fetched in same-top-level-site shared worker: ${response_2}`);
+      }
+
+      resolve();
+    } catch (e) {
+      reject(e);
+    }
+  });
+}, "Blob URL shouldn't be fetched from a cross-partition shared worker");
+
+// Tests fetching blob URL from a cross partition service worker.
+promise_test(t => {
+  return new Promise(async (resolve, reject) => {
+    try {
+      const response_queue_uuid = token();
+
+      const [iframe_1_uuid, iframe_2_uuid] =
+        await create_test_iframes(t, response_queue_uuid);
+
+      const blob = new Blob(["blob data"], {type : "text/plain"});
+      const blob_url = window.URL.createObjectURL(blob);
+      t.add_cleanup(() => window.URL.revokeObjectURL(blob_url));
+
+      // Create a service worker in cross-top-level-site iframe.
+      await send(iframe_1_uuid, create_service_worker_js(same_site_origin, response_queue_uuid));
+      var worker_1_uuid = await receive(response_queue_uuid);
+      t.add_cleanup(() =>
+        send(worker_1_uuid, "self.registration.unregister();"));
+
+      await send(worker_1_uuid,
+           can_blob_url_be_fetched_js(blob_url, response_queue_uuid));
+      const response_1 = await receive(response_queue_uuid);
+      if (response_1 !== fetch_unsuccessful_response) {
+        reject(`Blob URL was fetched in not-same-top-level-site service worker: ${response_1}`);
+      }
+
+      // Create a service worker in same-top-level-site iframe.
+      await send(iframe_2_uuid, create_service_worker_js(same_site_origin, response_queue_uuid));
+      var worker_2_uuid = await receive(response_queue_uuid);
+      t.add_cleanup(() =>
+        send(worker_2_uuid, "self.registration.unregister();"));
+
+      await send(worker_2_uuid,
+           can_blob_url_be_fetched_js(blob_url, response_queue_uuid));
+      const response_2 = await receive(response_queue_uuid);
+      if (response_2 !== fetch_successful_response) {
+        reject(`Blob URL wasn't fetched in same-top-level-site service worker: ${response_2}`);
+      }
+      resolve();
+    } catch (e) {
+      reject(e);
+    }
+  });
+}, "Blob URL shouldn't be fetched from a cross-partition service worker");
+
 </script>
-</body>
+</body>
\ No newline at end of file
diff --git a/test/fixtures/wpt/FileAPI/blob/Blob-constructor.any.js b/test/fixtures/wpt/FileAPI/blob/Blob-constructor.any.js
index 6dc44e8e156cce3..57a85624340e56c 100644
--- a/test/fixtures/wpt/FileAPI/blob/Blob-constructor.any.js
+++ b/test/fixtures/wpt/FileAPI/blob/Blob-constructor.any.js
@@ -290,14 +290,22 @@ test_blob(function() {
     new Int16Array([0x4150, 0x5353]),
     new Uint32Array([0x53534150]),
     new Int32Array([0x53534150]),
-    new Float16Array([2.65625, 58.59375]),
     new Float32Array([0xD341500000])
   ]);
 }, {
-  expected: "PASSPASSPASSPASSPASSPASSPASSPASS",
+  expected: "PASSPASSPASSPASSPASSPASSPASS",
   type: "",
   desc: "Passing typed arrays as elements of the blobParts array should work."
 });
+test_blob(function() {
+  return new Blob([
+    new Float16Array([2.65625, 58.59375])
+  ]);
+}, {
+  expected: "PASS",
+  type: "",
+  desc: "Passing a Float16Array as element of the blobParts array should work."
+});
 test_blob(function() {
   return new Blob([
     // 0x535 3415053534150
diff --git a/test/fixtures/wpt/README.md b/test/fixtures/wpt/README.md
index e5565462a120290..b6d74867ce66e95 100644
--- a/test/fixtures/wpt/README.md
+++ b/test/fixtures/wpt/README.md
@@ -10,32 +10,32 @@ See [test/wpt](../../wpt/README.md) for information on how these tests are run.
 
 Last update:
 
-- common: https://github.com/web-platform-tests/wpt/tree/dbd648158d/common
-- compression: https://github.com/web-platform-tests/wpt/tree/5aa50dd415/compression
-- console: https://github.com/web-platform-tests/wpt/tree/767ae35464/console
-- dom/abort: https://github.com/web-platform-tests/wpt/tree/d1f1ecbd52/dom/abort
-- dom/events: https://github.com/web-platform-tests/wpt/tree/ab8999891c/dom/events
+- common: https://github.com/web-platform-tests/wpt/tree/d8da9d4d1d/common
+- compression: https://github.com/web-platform-tests/wpt/tree/da8d6860b2/compression
+- console: https://github.com/web-platform-tests/wpt/tree/e48251b778/console
+- dom/abort: https://github.com/web-platform-tests/wpt/tree/07a9d09a8f/dom/abort
+- dom/events: https://github.com/web-platform-tests/wpt/tree/0a811c5161/dom/events
 - encoding: https://github.com/web-platform-tests/wpt/tree/5aa50dd415/encoding
 - fetch/data-urls/resources: https://github.com/web-platform-tests/wpt/tree/7c79d998ff/fetch/data-urls/resources
-- FileAPI: https://github.com/web-platform-tests/wpt/tree/cceaf3628d/FileAPI
-- hr-time: https://github.com/web-platform-tests/wpt/tree/34cafd797e/hr-time
+- FileAPI: https://github.com/web-platform-tests/wpt/tree/1d5fb397da/FileAPI
+- hr-time: https://github.com/web-platform-tests/wpt/tree/614e81711c/hr-time
 - html/webappapis/atob: https://github.com/web-platform-tests/wpt/tree/f267e1dca6/html/webappapis/atob
-- html/webappapis/microtask-queuing: https://github.com/web-platform-tests/wpt/tree/2c5c3c4c27/html/webappapis/microtask-queuing
-- html/webappapis/structured-clone: https://github.com/web-platform-tests/wpt/tree/47d3fb280c/html/webappapis/structured-clone
-- html/webappapis/timers: https://github.com/web-platform-tests/wpt/tree/5873f2d8f1/html/webappapis/timers
-- interfaces: https://github.com/web-platform-tests/wpt/tree/e90ece61d6/interfaces
-- performance-timeline: https://github.com/web-platform-tests/wpt/tree/17ebc3aea0/performance-timeline
-- resource-timing: https://github.com/web-platform-tests/wpt/tree/22d38586d0/resource-timing
-- resources: https://github.com/web-platform-tests/wpt/tree/1e140d63ec/resources
-- streams: https://github.com/web-platform-tests/wpt/tree/2bd26e124c/streams
-- url: https://github.com/web-platform-tests/wpt/tree/6a39784534/url
+- html/webappapis/microtask-queuing: https://github.com/web-platform-tests/wpt/tree/22ecfc9bac/html/webappapis/microtask-queuing
+- html/webappapis/structured-clone: https://github.com/web-platform-tests/wpt/tree/c29dcddf37/html/webappapis/structured-clone
+- html/webappapis/timers: https://github.com/web-platform-tests/wpt/tree/7a0548ac47/html/webappapis/timers
+- interfaces: https://github.com/web-platform-tests/wpt/tree/ab18bf796b/interfaces
+- performance-timeline: https://github.com/web-platform-tests/wpt/tree/94caab7038/performance-timeline
+- resource-timing: https://github.com/web-platform-tests/wpt/tree/95e7763ca9/resource-timing
+- resources: https://github.com/web-platform-tests/wpt/tree/ff5b1bc4db/resources
+- streams: https://github.com/web-platform-tests/wpt/tree/b5f2d0c48a/streams
+- url: https://github.com/web-platform-tests/wpt/tree/30de089033/url
 - user-timing: https://github.com/web-platform-tests/wpt/tree/5ae85bf826/user-timing
-- wasm/jsapi: https://github.com/web-platform-tests/wpt/tree/cde25e7e3c/wasm/jsapi
-- wasm/webapi: https://github.com/web-platform-tests/wpt/tree/fd1b23eeaa/wasm/webapi
-- WebCryptoAPI: https://github.com/web-platform-tests/wpt/tree/5e042cbc4e/WebCryptoAPI
+- wasm/jsapi: https://github.com/web-platform-tests/wpt/tree/140f5c80fd/wasm/jsapi
+- wasm/webapi: https://github.com/web-platform-tests/wpt/tree/28456b73ca/wasm/webapi
+- WebCryptoAPI: https://github.com/web-platform-tests/wpt/tree/4993c18fa4/WebCryptoAPI
 - webidl/ecmascript-binding/es-exceptions: https://github.com/web-platform-tests/wpt/tree/a370aad338/webidl/ecmascript-binding/es-exceptions
-- webmessaging/broadcastchannel: https://github.com/web-platform-tests/wpt/tree/e97fac4791/webmessaging/broadcastchannel
-- webstorage: https://github.com/web-platform-tests/wpt/tree/9dafa89214/webstorage
+- webmessaging/broadcastchannel: https://github.com/web-platform-tests/wpt/tree/6495c91853/webmessaging/broadcastchannel
+- webstorage: https://github.com/web-platform-tests/wpt/tree/1291340aaa/webstorage
 
 [Web Platform Tests]: https://github.com/web-platform-tests/wpt
 [`git node wpt`]: https://github.com/nodejs/node-core-utils/blob/main/docs/git-node.md#git-node-wpt
diff --git a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/cfrg_curves_bits.js b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/cfrg_curves_bits.js
index ef6905e574c1581..da809278a87aa51 100644
--- a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/cfrg_curves_bits.js
+++ b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/cfrg_curves_bits.js
@@ -6,8 +6,6 @@ function define_tests() {
   // Verify the derive functions perform checks against the all-zero value results,
   // ensuring small-order points are rejected.
   // https://www.rfc-editor.org/rfc/rfc7748#section-6.1
-  // TODO: The spec states that the check must be done on use, but there is discussion about doing it on import.
-  // https://github.com/WICG/webcrypto-secure-curves/pull/13
   Object.keys(kSmallOrderPoint).forEach(function(algorithmName) {
       kSmallOrderPoint[algorithmName].forEach(function(test) {
           promise_test(async() => {
@@ -23,8 +21,8 @@ function define_tests() {
                                                  false, [])
                   derived = await subtle.deriveBits({name: algorithmName, public: publicKey}, privateKey, 8 * sizes[algorithmName]);
               } catch (err) {
-                  assert_false(privateKey === undefined, "Private key should be valid.");
-                  assert_false(publicKey === undefined, "Public key should be valid.");
+                  assert_true(privateKey !== undefined, "Private key should be valid.");
+                  assert_true(publicKey !== undefined, "Public key should be valid.");
                   assert_equals(err.name, "OperationError", "Should throw correct error, not " + err.name + ": " + err.message + ".");
               }
               assert_equals(derived, undefined, "Operation succeeded, but should not have.");
@@ -59,25 +57,6 @@ function define_tests() {
               });
           }, algorithmName + " mixed case parameters");
 
-          // Null length
-          // "Null" is not valid per the current spec
-          //   - https://github.com/w3c/webcrypto/issues/322
-          //   - https://github.com/w3c/webcrypto/issues/329
-          //
-          // Proposal for a spec change:
-          //   - https://github.com/w3c/webcrypto/pull/345
-          //
-          // This test case may be replaced by these new tests:
-          //   - https://github.com/web-platform-tests/wpt/pull/43400
-          promise_test(function(test) {
-              return subtle.deriveBits({name: algorithmName, public: publicKeys[algorithmName]}, privateKeys[algorithmName], null)
-              .then(function(derivation) {
-                  assert_true(equalBuffers(derivation, derivations[algorithmName]), "Derived correct bits");
-              }, function(err) {
-                  assert_unreached("deriveBits failed with error " + err.name + ": " + err.message);
-              });
-          }, algorithmName + " with null length");
-
           // Shorter than entire derivation per algorithm
           promise_test(function(test) {
               return subtle.deriveBits({name: algorithmName, public: publicKeys[algorithmName]}, privateKeys[algorithmName], 8 * sizes[algorithmName] - 32)
diff --git a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length.https.any.js b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length.https.any.js
new file mode 100644
index 000000000000000..0aee2e3c172d30a
--- /dev/null
+++ b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length.https.any.js
@@ -0,0 +1,11 @@
+// META: title=WebCryptoAPI: deriveBits() tests for the 'length' parameter
+// META: script=derived_bits_length.js
+// META: script=derived_bits_length_vectors.js
+// META: script=derived_bits_length_testcases.js
+
+// Define subtests from a `promise_test` to ensure the harness does not
+// complete before the subtests are available. `explicit_done` cannot be used
+// for this purpose because the global `done` function is automatically invoked
+// by the WPT infrastructure in dedicated worker tests defined using the
+// "multi-global" pattern.
+promise_test(define_tests, 'setup - define tests');
diff --git a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length.js b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length.js
new file mode 100644
index 000000000000000..5a7ed7eb50a0a0b
--- /dev/null
+++ b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length.js
@@ -0,0 +1,36 @@
+function define_tests() {
+    // May want to test prefixed implementations.
+    var subtle = self.crypto.subtle;
+
+    Object.keys(testCases).forEach(algorithm => {
+        let testData = algorithms[algorithm];
+        testCases[algorithm].forEach(testParam => {
+            promise_test(async() => {
+                let derivedBits, privateKey, publicKey;
+                try {
+                    privateKey = await subtle.importKey(testData.privateKey.format, testData.privateKey.data, testData.importAlg, false, ["deriveBits"]);
+                    if (testData.deriveAlg.public !== undefined) {
+                        publicKey = await subtle.importKey(testData.publicKey.format, testData.publicKey.data, testData.importAlg, false, []);
+                        testData.deriveAlg.public = publicKey;
+                    }
+                    if (testParam.length === "omitted")
+                        derivedBits = await subtle.deriveBits(testData.deriveAlg, privateKey);
+                    else
+                        derivedBits = await subtle.deriveBits(testData.deriveAlg, privateKey, testParam.length);
+                    if (testParam.expected === undefined) {
+                        assert_unreached("deriveBits should have thrown an OperationError exception.");
+                    }
+                    assert_array_equals(new Uint8Array(derivedBits), testParam.expected, "Derived bits do not match the expected result.");
+                } catch (err) {
+                    if (err instanceof AssertionError || testParam.expected !== undefined) {
+                        throw err;
+                    }
+                    assert_true(privateKey !== undefined, "Key should be valid.");
+                    assert_equals(err.name, "OperationError", "deriveBits correctly threw OperationError: " + err.message);
+                }
+            }, algorithm + " derivation with " + testParam.length + " as 'length' parameter");
+        });
+    });
+
+    return Promise.resolve("define_tests");
+}
diff --git a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length_testcases.js b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length_testcases.js
new file mode 100644
index 000000000000000..1bd7fbc2c859896
--- /dev/null
+++ b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length_testcases.js
@@ -0,0 +1,30 @@
+var testCases = {
+    "HKDF": [
+        {length: 256, expected: algorithms["HKDF"].derivation},
+        {length: 0, expected: undefined}, // explicitly disallowed, so should throw
+        {length: null, expected: undefined }, // should throw an exception
+        {length: undefined, expected: undefined }, // should throw an exception
+        {length: "omitted", expected: undefined }, // default value is null, so should throw
+    ],
+    "PBKDF2": [
+        {length: 256, expected: algorithms["PBKDF2"].derivation},
+        {length: 0, expected: undefined}, // explicitly disallowed, so should throw
+        {length: null, expected: undefined }, // should throw an exception
+        {length: undefined, expected: undefined }, // should throw an exception
+        {length: "omitted", expected: undefined }, // default value is null, so should throw
+    ],
+    "ECDH": [
+        {length: 256, expected: algorithms["ECDH"].derivation},
+        {length: 0, expected: emptyArray},
+        {length: null, expected: algorithms["ECDH"].derivation},
+        {length: undefined, expected: algorithms["ECDH"].derivation},
+        {length: "omitted", expected: algorithms["ECDH"].derivation }, // default value is null
+    ],
+    "X25519": [
+        {length: 256, expected: algorithms["X25519"].derivation},
+        {length: 0, expected: emptyArray},
+        {length: null, expected: algorithms["X25519"].derivation},
+        {length: undefined, expected: algorithms["X25519"].derivation},
+        {length: "omitted", expected: algorithms["X25519"].derivation }, // default value is null
+    ],
+}
diff --git a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length_vectors.js b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length_vectors.js
new file mode 100644
index 000000000000000..fa51f7d3f2b195d
--- /dev/null
+++ b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/derived_bits_length_vectors.js
@@ -0,0 +1,33 @@
+const emptyArray = new Uint8Array([]);
+const rawKey = new Uint8Array([85, 115, 101, 114, 115, 32, 115, 104, 111, 117, 108, 100, 32, 112, 105, 99, 107, 32, 108, 111, 110, 103, 32, 112, 97, 115, 115, 112, 104, 114, 97, 115, 101, 115, 32, 40, 110, 111, 116, 32, 117, 115, 101, 32, 115, 104, 111, 114, 116, 32, 112, 97, 115, 115, 119, 111, 114, 100, 115, 41, 33]);
+const salt = new Uint8Array([83, 111, 100, 105, 117, 109, 32, 67, 104, 108, 111, 114, 105, 100, 101, 32, 99, 111, 109, 112, 111, 117, 110, 100]);
+const info = new Uint8Array([72, 75, 68, 70, 32, 101, 120, 116, 114, 97, 32, 105, 110, 102, 111]);
+
+var algorithms = {
+    "HKDF": {
+        importAlg: {name: "HKDF"},
+        privateKey: {format: "raw", data: rawKey},
+        deriveAlg: {name: "HKDF", salt: salt, hash: "SHA-256", info: info},
+        derivation: new Uint8Array([49, 183, 214, 133, 48, 168, 99, 231, 23, 192, 129, 202, 105, 23, 182, 134, 80, 179, 221, 154, 41, 243, 6, 6, 226, 202, 209, 153, 190, 193, 77, 19]),
+    },
+    "PBKDF2": {
+        importAlg: {name: "PBKDF2"},
+        privateKey: {format: "raw", data: rawKey},
+        deriveAlg: {name: "PBKDF2", salt: salt, hash: "SHA-256", iterations: 100000},
+        derivation: new Uint8Array([17, 153, 45, 139, 129, 51, 17, 36, 76, 84, 75, 98, 41, 41, 69, 226, 8, 212, 3, 206, 189, 107, 149, 82, 161, 165, 98, 6, 93, 153, 88, 234]),
+    },
+    "ECDH": {
+        importAlg: {name: "ECDH",  namedCurve: "P-256"},
+        privateKey: {format: "pkcs8", data: new Uint8Array([48, 129, 135, 2, 1, 0, 48, 19, 6, 7, 42, 134, 72, 206, 61, 2, 1, 6, 8, 42, 134, 72, 206, 61, 3, 1, 7, 4, 109, 48, 107, 2, 1, 1, 4, 32, 15, 247, 79, 232, 241, 202, 175, 97, 92, 206, 241, 29, 217, 53, 114, 87, 98, 217, 216, 65, 236, 186, 185, 94, 170, 38, 68, 123, 52, 100, 245, 113, 161, 68, 3, 66, 0, 4, 140, 96, 11, 44, 102, 25, 45, 97, 158, 39, 210, 37, 107, 59, 151, 118, 178, 141, 30, 5, 246, 13, 234, 189, 98, 174, 123, 154, 211, 157, 224, 217, 59, 4, 102, 109, 199, 119, 14, 126, 207, 13, 211, 203, 203, 211, 110, 221, 107, 94, 220, 153, 81, 7, 55, 161, 237, 104, 46, 205, 112, 244, 10, 47])},
+        publicKey: {format: "spki", data: new Uint8Array([48, 89, 48, 19, 6, 7, 42, 134, 72, 206, 61, 2, 1, 6, 8, 42, 134, 72, 206, 61, 3, 1, 7, 3, 66, 0, 4, 154, 116, 32, 120, 126, 95, 77, 105, 211, 232, 34, 114, 115, 1, 109, 56, 224, 71, 129, 133, 223, 127, 238, 156, 142, 103, 60, 202, 211, 79, 126, 128, 254, 49, 141, 182, 221, 107, 119, 218, 99, 32, 165, 246, 151, 89, 9, 68, 23, 177, 52, 239, 138, 139, 116, 193, 101, 4, 57, 198, 115, 0, 90, 61])},
+        deriveAlg: {name: "ECDH", public: new Uint8Array ([])},
+        derivation: new Uint8Array([14, 143, 60, 77, 177, 178, 162, 131, 115, 90, 0, 220, 87, 31, 26, 232, 151, 28, 227, 35, 250, 17, 131, 137, 203, 95, 65, 196, 59, 61, 181, 161]),
+    },
+    "X25519": {
+        importAlg: {name: "X25519"},
+        privateKey: {format: "pkcs8", data: new Uint8Array([48, 46, 2, 1, 0, 48, 5, 6, 3, 43, 101, 110, 4, 34, 4, 32, 200, 131, 142, 118, 208, 87, 223, 183, 216, 201, 90, 105, 225, 56, 22, 10, 221, 99, 115, 253, 113, 164, 210, 118, 187, 86, 227, 168, 27, 100, 255, 97])},
+        publicKey: {format: "spki", data: new Uint8Array([48, 42, 48, 5, 6, 3, 43, 101, 110, 3, 33, 0, 28, 242, 177, 230, 2, 46, 197, 55, 55, 30, 215, 245, 62, 84, 250, 17, 84, 216, 62, 152, 235, 100, 234, 81, 250, 229, 179, 48, 124, 254, 151, 6])},
+        deriveAlg: {name: "X25519", public: new Uint8Array ([])},
+        derivation: new Uint8Array([39, 104, 64, 157, 250, 185, 158, 194, 59, 140, 137, 185, 63, 245, 136, 2, 149, 247, 97, 118, 8, 143, 137, 228, 61, 254, 190, 126, 161, 149, 0, 8]),
+    }
+};
diff --git a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/ecdh_bits.js b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/ecdh_bits.js
index cb9747a529fd535..36b29c20a282abb 100644
--- a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/ecdh_bits.js
+++ b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/ecdh_bits.js
@@ -55,25 +55,6 @@ function define_tests() {
                 });
             }, namedCurve + " mixed case parameters");
 
-            // Null length
-            // "Null" is not valid per the current spec
-            //   - https://github.com/w3c/webcrypto/issues/322
-            //   - https://github.com/w3c/webcrypto/issues/329
-            //
-            // Proposal for a spec change:
-            //   - https://github.com/w3c/webcrypto/pull/345
-            //
-            // This test case may be replaced by these new tests:
-            //   - https://github.com/web-platform-tests/wpt/pull/43400
-            promise_test(function(test) {
-                return subtle.deriveBits({name: "ECDH", public: publicKeys[namedCurve]}, privateKeys[namedCurve], null)
-                .then(function(derivation) {
-                    assert_true(equalBuffers(derivation, derivations[namedCurve]), "Derived correct bits");
-                }, function(err) {
-                    assert_unreached("deriveBits failed with error " + err.name + ": " + err.message);
-                });
-            }, namedCurve + " with null length");
-
             // Shorter than entire derivation per algorithm
             promise_test(function(test) {
                 return subtle.deriveBits({name: "ECDH", public: publicKeys[namedCurve]}, privateKeys[namedCurve], 8 * sizes[namedCurve] - 32)
diff --git a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/hkdf.js b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/hkdf.js
index 3903da5cddff941..b2dfda0257bc81b 100644
--- a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/hkdf.js
+++ b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/hkdf.js
@@ -139,25 +139,6 @@ function define_tests() {
                             });
                         }, testName + " with missing info");
 
-                        // length null (OperationError)
-                        // "Null" is not valid per the current spec
-                        //   - https://github.com/w3c/webcrypto/issues/322
-                        //   - https://github.com/w3c/webcrypto/issues/329
-                        //
-                        // Proposal for a spec change:
-                        //   - https://github.com/w3c/webcrypto/pull/345
-                        //
-                        // This test case may be replaced by these new tests:
-                        //   - https://github.com/web-platform-tests/wpt/pull/43400
-                        subsetTest(promise_test, function(test) {
-                            return subtle.deriveBits(algorithm, baseKeys[derivedKeySize], null)
-                            .then(function(derivation) {
-                                assert_unreached("null length should have thrown an OperationError");
-                            }, function(err) {
-                                assert_equals(err.name, "OperationError", "deriveBits with null length correctly threw OperationError: " + err.message);
-                            });
-                        }, testName + " with null length");
-
                         // length not multiple of 8 (OperationError)
                         subsetTest(promise_test, function(test) {
                             return subtle.deriveBits(algorithm, baseKeys[derivedKeySize], 44)
diff --git a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/pbkdf2.js b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/pbkdf2.js
index 4e4ae79d800a402..090806ceb6b3eaa 100644
--- a/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/pbkdf2.js
+++ b/test/fixtures/wpt/WebCryptoAPI/derive_bits_keys/pbkdf2.js
@@ -103,26 +103,6 @@ function define_tests() {
 
                         });
 
-                        // Test various error conditions for deriveBits below:
-                        // length null (OperationError)
-                        // "Null" is not valid per the current spec
-                        //   - https://github.com/w3c/webcrypto/issues/322
-                        //   - https://github.com/w3c/webcrypto/issues/329
-                        //
-                        // Proposal for a spec change:
-                        //   - https://github.com/w3c/webcrypto/pull/345
-                        //
-                        // This test case may be replaced by these new tests:
-                        //   - https://github.com/web-platform-tests/wpt/pull/43400
-                        subsetTest(promise_test, function(test) {
-                            return subtle.deriveBits({name: "PBKDF2", salt: salts[saltSize], hash: hashName, iterations: parseInt(iterations)}, baseKeys[passwordSize], null)
-                            .then(function(derivation) {
-                                assert_unreached("null length should have thrown an OperationError");
-                            }, function(err) {
-                                assert_equals(err.name, "OperationError", "deriveBits with null length correctly threw OperationError: " + err.message);
-                            });
-                        }, testName + " with null length");
-
                         // 0 length (OperationError)
                         subsetTest(promise_test, function(test) {
                             return subtle.deriveBits({name: "PBKDF2", salt: salts[saltSize], hash: hashName, iterations: parseInt(iterations)}, baseKeys[passwordSize], 0)
diff --git a/test/fixtures/wpt/WebCryptoAPI/getRandomValues.any.js b/test/fixtures/wpt/WebCryptoAPI/getRandomValues.any.js
index 1a3370ea13d2c0a..0437857f2faabc3 100644
--- a/test/fixtures/wpt/WebCryptoAPI/getRandomValues.any.js
+++ b/test/fixtures/wpt/WebCryptoAPI/getRandomValues.any.js
@@ -1,4 +1,15 @@
 // Step 1.
+test(function() {
+    assert_throws_dom("TypeMismatchError", function() {
+        self.crypto.getRandomValues(new Float16Array(6))
+    }, "Float16Array")
+
+    assert_throws_dom("TypeMismatchError", function() {
+        const len = 65536 / Float16Array.BYTES_PER_ELEMENT + 1;
+        self.crypto.getRandomValues(new Float16Array(len));
+    }, "Float16Array (too long)")
+}, "Float16 arrays");
+
 test(function() {
     assert_throws_dom("TypeMismatchError", function() {
         self.crypto.getRandomValues(new Float32Array(6))
diff --git a/test/fixtures/wpt/WebCryptoAPI/import_export/crashtests/importKey-unsettled-promise.https.any.js b/test/fixtures/wpt/WebCryptoAPI/import_export/crashtests/importKey-unsettled-promise.https.any.js
new file mode 100644
index 000000000000000..0ceeea390ebf97d
--- /dev/null
+++ b/test/fixtures/wpt/WebCryptoAPI/import_export/crashtests/importKey-unsettled-promise.https.any.js
@@ -0,0 +1,17 @@
+// META: title=WebCryptoAPI: Assure promise returned by importKey is settled.
+// META: timeout=long
+// META: script=/common/gc.js
+
+'use strict';
+
+promise_test(async () => {
+  const jwkKey = {};
+  const extractable = true;
+  crypto.subtle.importKey("jwk", jwkKey, {name: "UNSUPPORTED", hash: "SHA-224"}, extractable, []).then(
+      () => { assert_unreached("Unsupported algorithm should cause promise rejection")},
+      (err) => {
+        assert_equals(err.name, "NotSupportedError");
+      });
+  await garbageCollect();
+})
+
diff --git a/test/fixtures/wpt/WebCryptoAPI/sign_verify/eddsa.js b/test/fixtures/wpt/WebCryptoAPI/sign_verify/eddsa.js
index d77a88088311763..74452d26091ae28 100644
--- a/test/fixtures/wpt/WebCryptoAPI/sign_verify/eddsa.js
+++ b/test/fixtures/wpt/WebCryptoAPI/sign_verify/eddsa.js
@@ -1,363 +1,214 @@
 
 function run_test() {
-  setup({explicit_done: true});
-
   var subtle = self.crypto.subtle; // Change to test prefixed implementations
 
-  // When are all these tests really done? When all the promises they use have resolved.
-  var all_promises = [];
-
   // Source file [algorithm_name]_vectors.js provides the getTestVectors method
   // for the algorithm that drives these tests.
   var testVectors = getTestVectors();
 
-  // Test verification first, because signing tests rely on that working
   testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
-          promise_test(function(test) {
-              var operation = subtle.verify(algorithm, vector.publicKey, vector.signature, vector.data)
-              .then(function(is_verified) {
-                  assert_true(is_verified, "Signature verified");
-              }, function(err) {
-                  assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
-              });
-
-              return operation;
-          }, vector.name + " verification");
-
-      }, function(err) {
-          // We need a failed test if the importVectorKey operation fails, so
-          // we know we never tested verification.
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " verification");
-      });
-
-      all_promises.push(promise);
-  });
+      var algorithm = {name: vector.algorithmName};
 
-  // Test verification with an altered buffer after call
-  testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
-          promise_test(function(test) {
+      // Test verification first, because signing tests rely on that working
+      promise_test(async() => {
+          let isVerified = false;
+          let key;
+          try {
+              key = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, ["verify"]);
+              isVerified = await subtle.verify(algorithm, key, vector.signature, vector.data)
+          } catch (err) {
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
+          };
+          assert_true(isVerified, "Signature verified");
+      }, vector.name + " verification");
+
+      // Test verification with an altered buffer after call
+      promise_test(async() => {
+          let isVerified = false;
+          let key;
+          try {
+              key = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, ["verify"]);
               var signature = copyBuffer(vector.signature);
-              var operation = subtle.verify(algorithm, vector.publicKey, signature, vector.data)
-              .then(function(is_verified) {
-                  assert_true(is_verified, "Signature verified");
-              }, function(err) {
-                  assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
-              });
-
-              signature[0] = 255 - signature[0];
-              return operation;
-          }, vector.name + " verification with altered signature after call");
-      }, function(err) {
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " verification with altered signature after call");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Check for successful verification even if data is altered after call.
-  testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
-          promise_test(function(test) {
+              [isVerified] = await Promise.all([
+                  subtle.verify(algorithm, key, signature, vector.data),
+                  signature[0] = 255 - signature[0]
+              ]);
+          } catch (err) {
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
+          };
+          assert_true(isVerified, "Signature verified");
+      }, vector.name + " verification with altered signature after call");
+
+      // Check for successful verification even if data is altered after call.
+      promise_test(async() => {
+          let isVerified = false;
+          let key;
+          try {
+              key = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, ["verify"]);
               var data = copyBuffer(vector.data);
-              var operation = subtle.verify(algorithm, vector.publicKey, vector.signature, data)
-              .then(function(is_verified) {
-                  assert_true(is_verified, "Signature verified");
-              }, function(err) {
-                  assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
-              });
-
-              data[0] = 255 - data[0];
-              return operation;
-          }, vector.name + " with altered data after call");
-      }, function(err) {
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " with altered data after call");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Check for failures due to using privateKey to verify.
-  testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
-          promise_test(function(test) {
-              return subtle.verify(algorithm, vector.privateKey, vector.signature, vector.data)
-              .then(function(data) {
-                  assert_unreached("Should have thrown error for using privateKey to verify in " + vector.name + ": " + err.message + "'");
-              }, function(err) {
-                  assert_equals(err.name, "InvalidAccessError", "Should throw InvalidAccessError instead of '" + err.message + "'");
-              });
-          }, vector.name + " using privateKey to verify");
-
-      }, function(err) {
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " using privateKey to verify");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Check for failures due to using publicKey to sign.
-  testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
-          promise_test(function(test) {
-              return subtle.sign(algorithm, vector.publicKey, vector.data)
-              .then(function(signature) {
-                  assert_unreached("Should have thrown error for using publicKey to sign in " + vector.name + ": " + err.message + "'");
-              }, function(err) {
-                  assert_equals(err.name, "InvalidAccessError", "Should throw InvalidAccessError instead of '" + err.message + "'");
-              });
-          }, vector.name + " using publicKey to sign");
-      }, function(err) {
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " using publicKey to sign");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Check for failures due to no "verify" usage.
-  testVectors.forEach(function(originalVector) {
-      var vector = Object.assign({}, originalVector);
-
-      var promise = importVectorKeys(vector, [], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
-          promise_test(function(test) {
-              return subtle.verify(algorithm, vector.publicKey, vector.signature, vector.data)
-              .then(function(data) {
-                  assert_unreached("Should have thrown error for no verify usage in " + vector.name + ": " + err.message + "'");
-              }, function(err) {
-                  assert_equals(err.name, "InvalidAccessError", "Should throw InvalidAccessError instead of '" + err.message + "'");
-              });
-          }, vector.name + " no verify usage");
-      }, function(err) {
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " no verify usage");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Check for successful signing and verification.
-  testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
-          promise_test(function(test) {
-              return subtle.sign(algorithm, vector.privateKey, vector.data)
-              .then(function(signature) {
-                  assert_true(equalBuffers(signature, vector.signature), "Signing did not give the expected output");
-                  // Can we verify the signature?
-                  return subtle.verify(algorithm, vector.publicKey, signature, vector.data)
-                  .then(function(is_verified) {
-                      assert_true(is_verified, "Round trip verification works");
-                      return signature;
-                  }, function(err) {
-                      assert_unreached("verify error for test " + vector.name + ": " + err.message + "'");
-                  });
-              }, function(err) {
-                  assert_unreached("sign error for test " + vector.name + ": '" + err.message + "'");
-              });
-          }, vector.name + " round trip");
-
-      }, function(err) {
-          // We need a failed test if the importVectorKey operation fails, so
-          // we know we never tested signing or verifying
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " round trip");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Test signing with the wrong algorithm
-  testVectors.forEach(function(vector) {
-      // Want to get the key for the wrong algorithm
-      var promise = subtle.generateKey({name: "HMAC", hash: "SHA-1"}, false, ["sign", "verify"])
-      .then(function(wrongKey) {
-          var algorithm = {name: vector.algorithmName};
-          return importVectorKeys(vector, ["verify"], ["sign"])
-          .then(function(vectors) {
-              promise_test(function(test) {
-                  var operation = subtle.sign(algorithm, wrongKey, vector.data)
-                  .then(function(signature) {
-                      assert_unreached("Signing should not have succeeded for " + vector.name);
-                  }, function(err) {
-                      assert_equals(err.name, "InvalidAccessError", "Should have thrown InvalidAccessError instead of '" + err.message + "'");
-                  });
-
-                  return operation;
-              }, vector.name + " signing with wrong algorithm name");
-
-          }, function(err) {
-              // We need a failed test if the importVectorKey operation fails, so
-              // we know we never tested verification.
-              promise_test(function(test) {
-                  assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-              }, "importVectorKeys step: " + vector.name + " signing with wrong algorithm name");
-          });
-      }, function(err) {
-          promise_test(function(test) {
-              assert_unreached("Generate wrong key for test " + vector.name + " failed: '" + err.message + "'");
-          }, "generate wrong key step: " + vector.name + " signing with wrong algorithm name");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Test verification with the wrong algorithm
-  testVectors.forEach(function(vector) {
-      // Want to get the key for the wrong algorithm
-      var promise = subtle.generateKey({name: "HMAC", hash: "SHA-1"}, false, ["sign", "verify"])
-      .then(function(wrongKey) {
-          return importVectorKeys(vector, ["verify"], ["sign"])
-          .then(function(vectors) {
-              var algorithm = {name: vector.algorithmName};
-              promise_test(function(test) {
-                  var operation = subtle.verify(algorithm, wrongKey, vector.signature, vector.data)
-                  .then(function(signature) {
-                      assert_unreached("Verifying should not have succeeded for " + vector.name);
-                  }, function(err) {
-                      assert_equals(err.name, "InvalidAccessError", "Should have thrown InvalidAccessError instead of '" + err.message + "'");
-                  });
-
-                  return operation;
-              }, vector.name + " verifying with wrong algorithm name");
-
-          }, function(err) {
-              // We need a failed test if the importVectorKey operation fails, so
-              // we know we never tested verification.
-              promise_test(function(test) {
-                  assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-              }, "importVectorKeys step: " + vector.name + " verifying with wrong algorithm name");
-          });
-      }, function(err) {
-          promise_test(function(test) {
-              assert_unreached("Generate wrong key for test " + vector.name + " failed: '" + err.message + "'");
-          }, "generate wrong key step: " + vector.name + " verifying with wrong algorithm name");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Test verification fails with wrong signature
-  testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
+              [isVerified] = await Promise.all([
+                  subtle.verify(algorithm, key, vector.signature, data),
+                  data[0] = 255 - data[0]
+              ]);
+          } catch (err) {
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
+          };
+          assert_true(isVerified, "Signature verified");
+      }, vector.name + " with altered data after call");
+
+      // Check for failures due to using privateKey to verify.
+      promise_test(async() => {
+          let isVerified = false;
+          let key;
+          try {
+              key = await subtle.importKey("pkcs8", vector.privateKeyBuffer, algorithm, false, ["sign"]);
+              isVerified = await subtle.verify(algorithm, key, vector.signature, vector.data)
+              assert_unreached("Should have thrown error for using privateKey to verify in " + vector.name);
+          } catch (err) {
+              if (err instanceof AssertionError)
+                  throw err;
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_equals(err.name, "InvalidAccessError", "Should throw InvalidAccessError instead of '" + err.message + "'");
+          };
+          assert_false(isVerified, "Signature verified");
+      }, vector.name + " using privateKey to verify");
+
+      // Check for failures due to using publicKey to sign.
+      promise_test(async() => {
+          let isVerified = false;
+          let key;
+          try {
+              key = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, ["verify"]);
+              let signature = await subtle.sign(algorithm, key, vector.data);
+              assert_unreached("Should have thrown error for using publicKey to sign in " + vector.name);
+          } catch (err) {
+              if (err instanceof AssertionError)
+                  throw err;
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_equals(err.name, "InvalidAccessError", "Should throw InvalidAccessError instead of '" + err.message + "'");
+          };
+      }, vector.name + " using publicKey to sign");
+
+      // Check for failures due to no "verify" usage.
+      promise_test(async() => {
+          let isVerified = false;
+          let key;
+          try {
+              key = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, []);
+              isVerified = await subtle.verify(algorithm, key, vector.signature, vector.data)
+              assert_unreached("Should have thrown error for no verify usage in " + vector.name);
+          } catch (err) {
+              if (err instanceof AssertionError)
+                  throw err;
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_equals(err.name, "InvalidAccessError", "Should throw InvalidAccessError instead of '" + err.message + "'");
+          };
+          assert_false(isVerified, "Signature verified");
+      }, vector.name + " no verify usage");
+
+      // Check for successful signing and verification.
+      var algorithm = {name: vector.algorithmName};
+      promise_test(async() => {
+          let isVerified = false;
+          let privateKey, publicKey;
+          let signature;
+          try {
+              privateKey = await subtle.importKey("pkcs8", vector.privateKeyBuffer, algorithm, false, ["sign"]);
+              publicKey = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, ["verify"]);
+              signature = await subtle.sign(algorithm, privateKey, vector.data);
+              isVerified = await subtle.verify(algorithm, publicKey, vector.signature, vector.data)
+          } catch (err) {
+              assert_false(publicKey === undefined || privateKey === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_false(signature === undefined, "sign error for test " + vector.name + ": '" + err.message + "'");
+              assert_unreached("verify error for test " + vector.name + ": " + err.message + "'");
+          };
+          assert_true(isVerified, "Round trip verification works");
+      }, vector.name + " round trip");
+
+      // Test signing with the wrong algorithm
+      var algorithm = {name: vector.algorithmName};
+      promise_test(async() => {
+          let wrongKey;
+          try {
+              wrongKey = await subtle.generateKey({name: "HMAC", hash: "SHA-1"}, false, ["sign", "verify"])
+              let signature = await subtle.sign(algorithm, wrongKey, vector.data);
+              assert_unreached("Signing should not have succeeded for " + vector.name);
+          } catch (err) {
+              if (err instanceof AssertionError)
+                  throw err;
+              assert_false(wrongKey === undefined, "Generate wrong key for test " + vector.name + " failed: '" + err.message + "'");
+              assert_equals(err.name, "InvalidAccessError", "Should have thrown InvalidAccessError instead of '" + err.message + "'");
+          };
+      }, vector.name + " signing with wrong algorithm name");
+
+      // Test verification with the wrong algorithm
+      var algorithm = {name: vector.algorithmName};
+      promise_test(async() => {
+          let wrongKey;
+          try {
+              wrongKey = await subtle.generateKey({name: "HMAC", hash: "SHA-1"}, false, ["sign", "verify"])
+              let isVerified = await subtle.verify(algorithm, wrongKey, vector.signature, vector.data)
+              assert_unreached("Verifying should not have succeeded for " + vector.name);
+          } catch (err) {
+              if (err instanceof AssertionError)
+                  throw err;
+              assert_false(wrongKey === undefined, "Generate wrong key for test " + vector.name + " failed: '" + err.message + "'");
+              assert_equals(err.name, "InvalidAccessError", "Should have thrown InvalidAccessError instead of '" + err.message + "'");
+          };
+      }, vector.name + " verifying with wrong algorithm name");
+
+      // Test verification fails with wrong signature
+      var algorithm = {name: vector.algorithmName};
+      promise_test(async() => {
+          let key;
+          let isVerified = true;
           var signature = copyBuffer(vector.signature);
           signature[0] = 255 - signature[0];
-          promise_test(function(test) {
-              var operation = subtle.verify(algorithm, vector.publicKey, signature, vector.data)
-              .then(function(is_verified) {
-                  assert_false(is_verified, "Signature NOT verified");
-              }, function(err) {
-                  assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
-              });
-
-              return operation;
-          }, vector.name + " verification failure due to altered signature");
-
-      }, function(err) {
-          // We need a failed test if the importVectorKey operation fails, so
-          // we know we never tested verification.
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " verification failure due to altered signature");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Test verification fails with short (odd length) signature
-  testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
+          try {
+              key = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, ["verify"]);
+              isVerified = await subtle.verify(algorithm, key, signature, vector.data)
+          } catch (err) {
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
+          };
+          assert_false(isVerified, "Signature verified");
+      }, vector.name + " verification failure due to altered signature");
+
+      // Test verification fails with short (odd length) signature
+      promise_test(async() => {
+          let key;
+          let isVerified = true;
           var signature = vector.signature.slice(1); // Skip the first byte
-          promise_test(function(test) {
-              var operation = subtle.verify(algorithm, vector.publicKey, signature, vector.data)
-              .then(function(is_verified) {
-                  assert_false(is_verified, "Signature NOT verified");
-              }, function(err) {
-                  assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
-              });
-
-              return operation;
-          }, vector.name + " verification failure due to shortened signature");
-
-      }, function(err) {
-          // We need a failed test if the importVectorKey operation fails, so
-          // we know we never tested verification.
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " verification failure due to shortened signature");
-      });
-
-      all_promises.push(promise);
-  });
-
-  // Test verification fails with wrong data
-  testVectors.forEach(function(vector) {
-      var promise = importVectorKeys(vector, ["verify"], ["sign"])
-      .then(function(vectors) {
-          var algorithm = {name: vector.algorithmName};
+          try {
+              key = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, ["verify"]);
+              isVerified = await subtle.verify(algorithm, key, signature, vector.data)
+          } catch (err) {
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
+          };
+          assert_false(isVerified, "Signature verified");
+      }, vector.name + " verification failure due to shortened signature");
+
+      // Test verification fails with wrong data
+      promise_test(async() => {
+          let key;
+          let isVerified = true;
           var data = copyBuffer(vector.data);
           data[0] = 255 - data[0];
-          promise_test(function(test) {
-              var operation = subtle.verify(algorithm, vector.publicKey, vector.signature, data)
-              .then(function(is_verified) {
-                  assert_false(is_verified, "Signature NOT verified");
-              }, function(err) {
-                  assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
-              });
-
-              return operation;
-          }, vector.name + " verification failure due to altered data");
-
-      }, function(err) {
-          // We need a failed test if the importVectorKey operation fails, so
-          // we know we never tested verification.
-          promise_test(function(test) {
-              assert_unreached("importVectorKeys failed for " + vector.name + ". Message: ''" + err.message + "''");
-          }, "importVectorKeys step: " + vector.name + " verification failure due to altered data");
-      });
-
-      all_promises.push(promise);
-  });
-
-
-  promise_test(function() {
-      return Promise.all(all_promises)
-          .then(function() {done();})
-          .catch(function() {done();})
-  }, "setup");
-
-  // Test that generated keys are valid for signing and verifying.
-  testVectors.forEach(function(vector) {
-      var algorithm = {name: vector.algorithmName};
+          try {
+              key = await subtle.importKey("spki", vector.publicKeyBuffer, algorithm, false, ["verify"]);
+              isVerified = await subtle.verify(algorithm, key, vector.signature, data)
+          } catch (err) {
+              assert_false(key === undefined, "importKey failed for " + vector.name + ". Message: ''" + err.message + "''");
+              assert_unreached("Verification should not throw error " + vector.name + ": " + err.message + "'");
+          };
+          assert_false(isVerified, "Signature verified");
+      }, vector.name + " verification failure due to altered data");
+
+      // Test that generated keys are valid for signing and verifying.
       promise_test(async() => {
           let key = await subtle.generateKey(algorithm, false, ["sign", "verify"]);
           let signature = await subtle.sign(algorithm, key.privateKey, vector.data);
@@ -366,41 +217,25 @@ function run_test() {
       }, "Sign and verify using generated " + vector.algorithmName + " keys.");
   });
 
-
-  // A test vector has all needed fields for signing and verifying, EXCEPT that the
-  // key field may be null. This function replaces that null with the Correct
-  // CryptoKey object.
-  //
-  // Returns a Promise that yields an updated vector on success.
-  function importVectorKeys(vector, publicKeyUsages, privateKeyUsages) {
-      var publicPromise, privatePromise;
-
-      if (vector.publicKey !== null) {
-          publicPromise = new Promise(function(resolve, reject) {
-              resolve(vector);
-          });
-      } else {
-          publicPromise = subtle.importKey(vector.publicKeyFormat, vector.publicKeyBuffer, {name: vector.algorithmName}, false, publicKeyUsages)
-          .then(function(key) {
-              vector.publicKey = key;
-              return vector;
-          });        // Returns a copy of the sourceBuffer it is sent.
-      }
-
-      if (vector.privateKey !== null) {
-          privatePromise = new Promise(function(resolve, reject) {
-              resolve(vector);
-          });
-      } else {
-          privatePromise = subtle.importKey(vector.privateKeyFormat, vector.privateKeyBuffer, {name: vector.algorithmName}, false, privateKeyUsages)
-          .then(function(key) {
-              vector.privateKey = key;
-              return vector;
-          });
-      }
-
-      return Promise.all([publicPromise, privatePromise]);
-  }
+  // When verifying an Ed25519 or Ed448 signature, if the public key or the first half of the signature (R) is
+  // an invalid or small-order element, return false.
+  Object.keys(kSmallOrderTestCases).forEach(function (algorithmName) {
+      var algorithm = {name: algorithmName};
+      kSmallOrderTestCases[algorithmName].forEach(function(test) {
+          promise_test(async() => {
+              let isVerified = true;
+              let publicKey;
+              try {
+                  publicKey = await subtle.importKey("raw", test.keyData, algorithm, false, ["verify"])
+                  isVerified = await subtle.verify(algorithm, publicKey, test.signature, test.message);
+              } catch (err) {
+                  assert_true(publicKey !== undefined, "Public key should be valid.");
+                  assert_unreached("The operation shouldn't fail, but it thown this error: " + err.name + ": " + err.message + ".");
+              }
+              assert_equals(isVerified, test.verified, "Signature verification result.");
+          }, algorithmName + " Verification checks with small-order key of order - Test " + test.id);
+      });
+  });
 
   // Returns a copy of the sourceBuffer it is sent.
   function copyBuffer(sourceBuffer) {
diff --git a/test/fixtures/wpt/WebCryptoAPI/sign_verify/eddsa_vectors.js b/test/fixtures/wpt/WebCryptoAPI/sign_verify/eddsa_vectors.js
index 96ec2b01af96f2f..ce80e0ea7e26267 100644
--- a/test/fixtures/wpt/WebCryptoAPI/sign_verify/eddsa_vectors.js
+++ b/test/fixtures/wpt/WebCryptoAPI/sign_verify/eddsa_vectors.js
@@ -53,6 +53,145 @@ function getTestVectors() {
 
     vectors.push(vector);
   });
-
   return vectors;
 }
+
+// https://eprint.iacr.org/2020/1244.pdf#table.caption.3
+var kSmallOrderPoints = [
+    // Canonical serializations
+    [0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00], // #0 - Order 1
+    [0xEC, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F], // #1 - Order 2
+    [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80], // #2 - Order 4
+    [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00], // #3 - Order 4
+    [0xC7, 0x17, 0x6A, 0x70, 0x3D, 0x4D, 0xD8, 0x4F, 0xBA, 0x3C, 0x0B, 0x76, 0x0D, 0x10, 0x67, 0x0F, 0x2A, 0x20, 0x53, 0xFA, 0x2C, 0x39, 0xCC, 0xC6, 0x4E, 0xC7, 0xFD, 0x77, 0x92, 0xAC, 0x03, 0x7A], // #4 - Order 8
+    [0xC7, 0x17, 0x6A, 0x70, 0x3D, 0x4D, 0xD8, 0x4F, 0xBA, 0x3C, 0x0B, 0x76, 0x0D, 0x10, 0x67, 0x0F, 0x2A, 0x20, 0x53, 0xFA, 0x2C, 0x39, 0xCC, 0xC6, 0x4E, 0xC7, 0xFD, 0x77, 0x92, 0xAC, 0x03, 0xFA], // #5 - Order 8
+    [0x26, 0xE8, 0x95, 0x8F, 0xC2, 0xB2, 0x27, 0xB0, 0x45, 0xC3, 0xF4, 0x89, 0xF2, 0xEF, 0x98, 0xF0, 0xD5, 0xDF, 0xAC, 0x05, 0xD3, 0xC6, 0x33, 0x39, 0xB1, 0x38, 0x02, 0x88, 0x6D, 0x53, 0xFC, 0x05], // #6 - Order 8
+    [0x26, 0xE8, 0x95, 0x8F, 0xC2, 0xB2, 0x27, 0xB0, 0x45, 0xC3, 0xF4, 0x89, 0xF2, 0xEF, 0x98, 0xF0, 0xD5, 0xDF, 0xAC, 0x05, 0xD3, 0xC6, 0x33, 0x39, 0xB1, 0x38, 0x02, 0x88, 0x6D, 0x53, 0xFC, 0x85], // #7 - Order 8
+
+    // Non-canonical serializatons
+    [0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80], // #8  - Order 1
+    [0xEC, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF], // #9  - Order 2
+    [0xEE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F], // #10 - Order 1
+    [0xEE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF], // #11 - Order 1
+    [0xED, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF], // #12 - Order 4
+    [0xED, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F], // #13 - Order 4
+];
+
+
+var pubKeys = [
+    [0xc7, 0x17, 0x6a, 0x70, 0x3d, 0x4d, 0xd8, 0x4f, 0xba, 0x3c, 0x0b, 0x76, 0x0d, 0x10, 0x67, 0x0f, 0x2a, 0x20, 0x53, 0xfa, 0x2c, 0x39, 0xcc, 0xc6, 0x4e, 0xc7, 0xfd, 0x77, 0x92, 0xac, 0x03, 0xfa], // kSmallOrderPoints #5
+    [0xf7, 0xba, 0xde, 0xc5, 0xb8, 0xab, 0xea, 0xf6, 0x99, 0x58, 0x39, 0x92, 0x21, 0x9b, 0x7b, 0x22, 0x3f, 0x1d, 0xf3, 0xfb, 0xbe, 0xa9, 0x19, 0x84, 0x4e, 0x3f, 0x7c, 0x55, 0x4a, 0x43, 0xdd, 0x43], // highest 32 bytes of case "1" signature
+    [0xcd, 0xb2, 0x67, 0xce, 0x40, 0xc5, 0xcd, 0x45, 0x30, 0x6f, 0xa5, 0xd2, 0xf2, 0x97, 0x31, 0x45, 0x93, 0x87, 0xdb, 0xf9, 0xeb, 0x93, 0x3b, 0x7b, 0xd5, 0xae, 0xd9, 0xa7, 0x65, 0xb8, 0x8d, 0x4d],
+    [0x44, 0x2a, 0xad, 0x9f, 0x08, 0x9a, 0xd9, 0xe1, 0x46, 0x47, 0xb1, 0xef, 0x90, 0x99, 0xa1, 0xff, 0x47, 0x98, 0xd7, 0x85, 0x89, 0xe6, 0x6f, 0x28, 0xec, 0xa6, 0x9c, 0x11, 0xf5, 0x82, 0xa6, 0x23],
+    [0xec, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff], // kSmallOrderPoints #9
+    [0xEC, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F], // kSmallOrderPoints #1
+]
+
+// https://eprint.iacr.org/2020/1244.pdf
+// signature = (R, S); public key A, h = SHA512(R||A||M )
+// 8(SB) = 8R + 8(hA) => (1)
+// SB = R + hA => (2)
+var kSmallOrderTestCases = {
+    "Ed25519": [
+        {
+            id: "0", // S = 0 | A's order = small | R's order = small | (1) = pass | (2) = pass
+            message : Uint8Array.from([0x8c, 0x93, 0x25, 0x5d, 0x71, 0xdc, 0xab, 0x10, 0xe8, 0xf3, 0x79, 0xc2, 0x62, 0x00, 0xf3, 0xc7, 0xbd, 0x5f, 0x09, 0xd9, 0xbc, 0x30, 0x68, 0xd3, 0xef, 0x4e, 0xde, 0xb4, 0x85, 0x30, 0x22, 0xb6]),
+            keyData : Uint8Array.from(pubKeys[0]),
+            signature : Uint8Array.from([0xc7, 0x17, 0x6a, 0x70, 0x3d, 0x4d, 0xd8, 0x4f, 0xba, 0x3c, 0x0b, 0x76, 0x0d, 0x10, 0x67, 0x0f, 0x2a, 0x20, 0x53, 0xfa, 0x2c, 0x39, 0xcc, 0xc6, 0x4e, 0xc7, 0xfd, 0x77, 0x92, 0xac, 0x03, 0x7a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
+            verified: false,  // small-order signature's R fail in the verification.
+        },
+        {
+            id: "1", // 0 < S < L | A's order = small | R's order = mixed | (1) = pass | (2) = pass
+            message : Uint8Array.from([0x9b, 0xd9, 0xf4, 0x4f, 0x4d, 0xcc, 0x75, 0xbd, 0x53, 0x1b, 0x56, 0xb2, 0xcd, 0x28, 0x0b, 0x0b, 0xb3, 0x8f, 0xc1, 0xcd, 0x6d, 0x12, 0x30, 0xe1, 0x48, 0x61, 0xd8, 0x61, 0xde, 0x09, 0x2e, 0x79]),
+            keyData : Uint8Array.from(pubKeys[0]),
+            signature : Uint8Array.from([0xf7, 0xba, 0xde, 0xc5, 0xb8, 0xab, 0xea, 0xf6, 0x99, 0x58, 0x39, 0x92, 0x21, 0x9b, 0x7b, 0x22, 0x3f, 0x1d, 0xf3, 0xfb, 0xbe, 0xa9, 0x19, 0x84, 0x4e, 0x3f, 0x7c, 0x55, 0x4a, 0x43, 0xdd, 0x43, 0xa5, 0xbb, 0x70, 0x47, 0x86, 0xbe, 0x79, 0xfc, 0x47, 0x6f, 0x91, 0xd3, 0xf3, 0xf8, 0x9b, 0x03, 0x98, 0x4d, 0x80, 0x68, 0xdc, 0xf1, 0xbb, 0x7d, 0xfc, 0x66, 0x37, 0xb4, 0x54, 0x50, 0xac, 0x04]),
+            verified: false, // small-order key's data fail in the verification.
+        },
+        {
+            id: "2", // 0 < S < L | A's order = mixed | R's order = small | (1) = pass | (2) = pass
+            message : Uint8Array.from([0xae, 0xbf, 0x3f, 0x26, 0x01, 0xa0, 0xc8, 0xc5, 0xd3, 0x9c, 0xc7, 0xd8, 0x91, 0x16, 0x42, 0xf7, 0x40, 0xb7, 0x81, 0x68, 0x21, 0x8d, 0xa8, 0x47, 0x17, 0x72, 0xb3, 0x5f, 0x9d, 0x35, 0xb9, 0xab]),
+            keyData : Uint8Array.from(pubKeys[1]),
+            signature : Uint8Array.from([0xc7, 0x17, 0x6a, 0x70, 0x3d, 0x4d, 0xd8, 0x4f, 0xba, 0x3c, 0x0b, 0x76, 0x0d, 0x10, 0x67, 0x0f, 0x2a, 0x20, 0x53, 0xfa, 0x2c, 0x39, 0xcc, 0xc6, 0x4e, 0xc7, 0xfd, 0x77, 0x92, 0xac, 0x03, 0xfa, 0x8c, 0x4b, 0xd4, 0x5a, 0xec, 0xac, 0xa5, 0xb2, 0x4f, 0xb9, 0x7b, 0xc1, 0x0a, 0xc2, 0x7a, 0xc8, 0x75, 0x1a, 0x7d, 0xfe, 0x1b, 0xaf, 0xf8, 0xb9, 0x53, 0xec, 0x9f, 0x58, 0x33, 0xca, 0x26, 0x0e]),
+            verified: false,  // small-order signature's R fail in the verification.
+        },
+        {
+            id: "3", // 0 < S < L | A's order = mixed | R's order = mixed | (1) = pass | (2) = pass
+            message : Uint8Array.from([0x9b, 0xd9, 0xf4, 0x4f, 0x4d, 0xcc, 0x75, 0xbd, 0x53, 0x1b, 0x56, 0xb2, 0xcd, 0x28, 0x0b, 0x0b, 0xb3, 0x8f, 0xc1, 0xcd, 0x6d, 0x12, 0x30, 0xe1, 0x48, 0x61, 0xd8, 0x61, 0xde, 0x09, 0x2e, 0x79]),
+            keyData : Uint8Array.from(pubKeys[2]),
+            signature : Uint8Array.from([0x90, 0x46, 0xa6, 0x47, 0x50, 0x44, 0x49, 0x38, 0xde, 0x19, 0xf2, 0x27, 0xbb, 0x80, 0x48, 0x5e, 0x92, 0xb8, 0x3f, 0xdb, 0x4b, 0x65, 0x06, 0xc1, 0x60, 0x48, 0x4c, 0x01, 0x6c, 0xc1, 0x85, 0x2f, 0x87, 0x90, 0x9e, 0x14, 0x42, 0x8a, 0x7a, 0x1d, 0x62, 0xe9, 0xf2, 0x2f, 0x3d, 0x3a, 0xd7, 0x80, 0x2d, 0xb0, 0x2e, 0xb2, 0xe6, 0x88, 0xb6, 0xc5, 0x2f, 0xcd, 0x66, 0x48, 0xa9, 0x8b, 0xd0, 0x09]),
+            verified: true, // mixed-order points are not checked.
+        },
+        {
+            id: "4", // 0 < S < L | A's order = mixed | R's order = mixed | (1) = pass | (2) = fail
+            message : Uint8Array.from([0xe4, 0x7d, 0x62, 0xc6, 0x3f, 0x83, 0x0d, 0xc7, 0xa6, 0x85, 0x1a, 0x0b, 0x1f, 0x33, 0xae, 0x4b, 0xb2, 0xf5, 0x07, 0xfb, 0x6c, 0xff, 0xec, 0x40, 0x11, 0xea, 0xcc, 0xd5, 0x5b, 0x53, 0xf5, 0x6c]),
+            keyData : Uint8Array.from(pubKeys[2]),
+            signature : Uint8Array.from([0x16, 0x0a, 0x1c, 0xb0, 0xdc, 0x9c, 0x02, 0x58, 0xcd, 0x0a, 0x7d, 0x23, 0xe9, 0x4d, 0x8f, 0xa8, 0x78, 0xbc, 0xb1, 0x92, 0x5f, 0x2c, 0x64, 0x24, 0x6b, 0x2d, 0xee, 0x17, 0x96, 0xbe, 0xd5, 0x12, 0x5e, 0xc6, 0xbc, 0x98, 0x2a, 0x26, 0x9b, 0x72, 0x3e, 0x06, 0x68, 0xe5, 0x40, 0x91, 0x1a, 0x9a, 0x6a, 0x58, 0x92, 0x1d, 0x69, 0x25, 0xe4, 0x34, 0xab, 0x10, 0xaa, 0x79, 0x40, 0x55, 0x1a, 0x09]),
+            verified: false, // expect a cofactorless verification algorithm.
+        },
+        {
+            id: "5", // 0 < S < L | A's order = mixed | R's order = L | (1) = pass | (2) = fail
+            message : Uint8Array.from([0xe4, 0x7d, 0x62, 0xc6, 0x3f, 0x83, 0x0d, 0xc7, 0xa6, 0x85, 0x1a, 0x0b, 0x1f, 0x33, 0xae, 0x4b, 0xb2, 0xf5, 0x07, 0xfb, 0x6c, 0xff, 0xec, 0x40, 0x11, 0xea, 0xcc, 0xd5, 0x5b, 0x53, 0xf5, 0x6c]),
+            keyData : Uint8Array.from(pubKeys[2]),
+            signature : Uint8Array.from([0x21, 0x12, 0x2a, 0x84, 0xe0, 0xb5, 0xfc, 0xa4, 0x05, 0x2f, 0x5b, 0x12, 0x35, 0xc8, 0x0a, 0x53, 0x78, 0x78, 0xb3, 0x8f, 0x31, 0x42, 0x35, 0x6b, 0x2c, 0x23, 0x84, 0xeb, 0xad, 0x46, 0x68, 0xb7, 0xe4, 0x0b, 0xc8, 0x36, 0xda, 0xc0, 0xf7, 0x10, 0x76, 0xf9, 0xab, 0xe3, 0xa5, 0x3f, 0x9c, 0x03, 0xc1, 0xce, 0xee, 0xdd, 0xb6, 0x58, 0xd0, 0x03, 0x04, 0x94, 0xac, 0xe5, 0x86, 0x68, 0x74, 0x05]),
+            verified: false, // expect a cofactorless verification algorithm.
+        },
+        {
+            id: "6", // S > L | A's order = L | R's order = L | (1) = pass | (2) = pass
+            message : Uint8Array.from([0x85, 0xe2, 0x41, 0xa0, 0x7d, 0x14, 0x8b, 0x41, 0xe4, 0x7d, 0x62, 0xc6, 0x3f, 0x83, 0x0d, 0xc7, 0xa6, 0x85, 0x1a, 0x0b, 0x1f, 0x33, 0xae, 0x4b, 0xb2, 0xf5, 0x07, 0xfb, 0x6c, 0xff, 0xec, 0x40]),
+            keyData : Uint8Array.from(pubKeys[3]),
+            signature : Uint8Array.from([0xe9, 0x6f, 0x66, 0xbe, 0x97, 0x6d, 0x82, 0xe6, 0x01, 0x50, 0xba, 0xec, 0xff, 0x99, 0x06, 0x68, 0x4a, 0xeb, 0xb1, 0xef, 0x18, 0x1f, 0x67, 0xa7, 0x18, 0x9a, 0xc7, 0x8e, 0xa2, 0x3b, 0x6c, 0x0e, 0x54, 0x7f, 0x76, 0x90, 0xa0, 0xe2, 0xdd, 0xcd, 0x04, 0xd8, 0x7d, 0xbc, 0x34, 0x90, 0xdc, 0x19, 0xb3, 0xb3, 0x05, 0x2f, 0x7f, 0xf0, 0x53, 0x8c, 0xb6, 0x8a, 0xfb, 0x36, 0x9b, 0xa3, 0xa5, 0x14]),
+            verified: false, // S out of bounds
+        },
+        {
+            id: "7", // S >> L | A's order = L | R's order = L | (1) = pass | (2) = pass
+            message : Uint8Array.from([0x85, 0xe2, 0x41, 0xa0, 0x7d, 0x14, 0x8b, 0x41, 0xe4, 0x7d, 0x62, 0xc6, 0x3f, 0x83, 0x0d, 0xc7, 0xa6, 0x85, 0x1a, 0x0b, 0x1f, 0x33, 0xae, 0x4b, 0xb2, 0xf5, 0x07, 0xfb, 0x6c, 0xff, 0xec, 0x40]),
+            keyData : Uint8Array.from(pubKeys[3]),
+            signature : Uint8Array.from([0x8c, 0xe5, 0xb9, 0x6c, 0x8f, 0x26, 0xd0, 0xab, 0x6c, 0x47, 0x95, 0x8c, 0x9e, 0x68, 0xb9, 0x37, 0x10, 0x4c, 0xd3, 0x6e, 0x13, 0xc3, 0x35, 0x66, 0xac, 0xd2, 0xfe, 0x8d, 0x38, 0xaa, 0x19, 0x42, 0x7e, 0x71, 0xf9, 0x8a, 0x47, 0x34, 0xe7, 0x4f, 0x2f, 0x13, 0xf0, 0x6f, 0x97, 0xc2, 0x0d, 0x58, 0xcc, 0x3f, 0x54, 0xb8, 0xbd, 0x0d, 0x27, 0x2f, 0x42, 0xb6, 0x95, 0xdd, 0x7e, 0x89, 0xa8, 0xc2, 0x02]),
+            verified: false, // S out of bounds
+        },
+        {
+            id: "8", // 0 < S < L | A's order = mixed | R's order = small (non-canonical) | (1) = ? | (2) = ? Implementations that reduce A before hashing will accept #8 and accept #9, and viceversa
+            message : Uint8Array.from([0x9b, 0xed, 0xc2, 0x67, 0x42, 0x37, 0x25, 0xd4, 0x73, 0x88, 0x86, 0x31, 0xeb, 0xf4, 0x59, 0x88, 0xba, 0xd3, 0xdb, 0x83, 0x85, 0x1e, 0xe8, 0x5c, 0x85, 0xe2, 0x41, 0xa0, 0x7d, 0x14, 0x8b, 0x41]),
+            keyData : Uint8Array.from(pubKeys[1]),
+            signature : Uint8Array.from([0xec, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x03, 0xbe, 0x96, 0x78, 0xac, 0x10, 0x2e, 0xdc, 0xd9, 0x2b, 0x02, 0x10, 0xbb, 0x34, 0xd7, 0x42, 0x8d, 0x12, 0xff, 0xc5, 0xdf, 0x5f, 0x37, 0xe3, 0x59, 0x94, 0x12, 0x66, 0xa4, 0xe3, 0x5f, 0x0f]),
+            verified: false, // non-canonical point should fail in the verificaton (RFC8032)
+        },
+        {
+            id: "9", // 0 < S < L | A's order = mixed | R's order = small (non-canonical) | (1) = ? | (2) = ?
+            message : Uint8Array.from([0x9b, 0xed, 0xc2, 0x67, 0x42, 0x37, 0x25, 0xd4, 0x73, 0x88, 0x86, 0x31, 0xeb, 0xf4, 0x59, 0x88, 0xba, 0xd3, 0xdb, 0x83, 0x85, 0x1e, 0xe8, 0x5c, 0x85, 0xe2, 0x41, 0xa0, 0x7d, 0x14, 0x8b, 0x41]),
+            keyData : Uint8Array.from(pubKeys[1]),
+            signature : Uint8Array.from([0xec, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xca, 0x8c, 0x5b, 0x64, 0xcd, 0x20, 0x89, 0x82, 0xaa, 0x38, 0xd4, 0x93, 0x66, 0x21, 0xa4, 0x77, 0x5a, 0xa2, 0x33, 0xaa, 0x05, 0x05, 0x71, 0x1d, 0x8f, 0xdc, 0xfd, 0xaa, 0x94, 0x3d, 0x49, 0x08]),
+            verified: false, // non-canonical point should fail in the verificaton (RFC8032)
+        },
+        {
+            id: "10", // 0 < S < L | A's order = small (non-canonical) | R's order = mixed | (1) = ? | (2) = ? Implementations that reduce A before hashing will accept #10 and accept #11, and viceversa
+            message : Uint8Array.from([0xe9, 0x6b, 0x70, 0x21, 0xeb, 0x39, 0xc1, 0xa1, 0x63, 0xb6, 0xda, 0x4e, 0x30, 0x93, 0xdc, 0xd3, 0xf2, 0x13, 0x87, 0xda, 0x4c, 0xc4, 0x57, 0x2b, 0xe5, 0x88, 0xfa, 0xfa, 0xe2, 0x3c, 0x15, 0x5b]),
+            keyData : Uint8Array.from(pubKeys[4]),
+            signature : Uint8Array.from([0xa9, 0xd5, 0x52, 0x60, 0xf7, 0x65, 0x26, 0x1e, 0xb9, 0xb8, 0x4e, 0x10, 0x6f, 0x66, 0x5e, 0x00, 0xb8, 0x67, 0x28, 0x7a, 0x76, 0x19, 0x90, 0xd7, 0x13, 0x59, 0x63, 0xee, 0x0a, 0x7d, 0x59, 0xdc, 0xa5, 0xbb, 0x70, 0x47, 0x86, 0xbe, 0x79, 0xfc, 0x47, 0x6f, 0x91, 0xd3, 0xf3, 0xf8, 0x9b, 0x03, 0x98, 0x4d, 0x80, 0x68, 0xdc, 0xf1, 0xbb, 0x7d, 0xfc, 0x66, 0x37, 0xb4, 0x54, 0x50, 0xac, 0x04]),
+            verified: false, // non-canonical point should fail in the verificaton (RFC8032)
+        },
+        {
+            id: "11", // 0 < S < L | A's order = small (non-canonical) | R's order = mixed | (1) = ? | (2) = ? Implementations that reduce A before hashing will accept #10 and accept #11, and viceversa
+            message : Uint8Array.from([0x39, 0xa5, 0x91, 0xf5, 0x32, 0x1b, 0xbe, 0x07, 0xfd, 0x5a, 0x23, 0xdc, 0x2f, 0x39, 0xd0, 0x25, 0xd7, 0x45, 0x26, 0x61, 0x57, 0x46, 0x72, 0x7c, 0xee, 0xfd, 0x6e, 0x82, 0xae, 0x65, 0xc0, 0x6f]),
+            keyData : Uint8Array.from(pubKeys[4]),
+            signature : Uint8Array.from([0xa9, 0xd5, 0x52, 0x60, 0xf7, 0x65, 0x26, 0x1e, 0xb9, 0xb8, 0x4e, 0x10, 0x6f, 0x66, 0x5e, 0x00, 0xb8, 0x67, 0x28, 0x7a, 0x76, 0x19, 0x90, 0xd7, 0x13, 0x59, 0x63, 0xee, 0x0a, 0x7d, 0x59, 0xdc, 0xa5, 0xbb, 0x70, 0x47, 0x86, 0xbe, 0x79, 0xfc, 0x47, 0x6f, 0x91, 0xd3, 0xf3, 0xf8, 0x9b, 0x03, 0x98, 0x4d, 0x80, 0x68, 0xdc, 0xf1, 0xbb, 0x7d, 0xfc, 0x66, 0x37, 0xb4, 0x54, 0x50, 0xac, 0x04]),
+            verified: false, // non-canonical point should fail in the verificaton (RFC8032)
+        },
+        // https://eprint.iacr.org/2020/1244.pdf#section.A.2
+        // cases breaking non-repudiation
+        {
+            id: "12", // 0 < S < L | A's order = small | R's order = mixed | (1) = ? | (2) = ?
+            message : Uint8Array.from([0x53, 0x65, 0x6e, 0x64, 0x20, 0x31, 0x30, 0x30, 0x20, 0x55, 0x53, 0x44, 0x20, 0x74, 0x6f, 0x20, 0x41, 0x6c, 0x69, 0x63, 0x65]),
+            keyData : Uint8Array.from(pubKeys[5]),
+            signature : Uint8Array.from([0xa9, 0xd5, 0x52, 0x60, 0xf7, 0x65, 0x26, 0x1e, 0xb9, 0xb8, 0x4e, 0x10, 0x6f, 0x66, 0x5e, 0x00, 0xb8, 0x67, 0x28, 0x7a, 0x76, 0x19, 0x90, 0xd7, 0x13, 0x59, 0x63, 0xee, 0x0a, 0x7d, 0x59, 0xdc, 0xa5, 0xbb, 0x70, 0x47, 0x86, 0xbe, 0x79, 0xfc, 0x47, 0x6f, 0x91, 0xd3, 0xf3, 0xf8, 0x9b, 0x03, 0x98, 0x4d, 0x80, 0x68, 0xdc, 0xf1, 0xbb, 0x7d, 0xfc, 0x66, 0x37, 0xb4, 0x54, 0x50, 0xac, 0x04]),
+            verified: false,
+        },
+        {
+            id: "13", // 0 < S < L | A's order = small | R's order = mixed | (1) = ? | (2) = ?
+            message : Uint8Array.from([0x53, 0x65, 0x6e, 0x64, 0x20, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x20, 0x55, 0x53, 0x44, 0x20, 0x74, 0x6f, 0x20, 0x41, 0x6c, 0x69, 0x63, 0x65]),
+            keyData : Uint8Array.from(pubKeys[5]),
+            signature : Uint8Array.from([0xa9, 0xd5, 0x52, 0x60, 0xf7, 0x65, 0x26, 0x1e, 0xb9, 0xb8, 0x4e, 0x10, 0x6f, 0x66, 0x5e, 0x00, 0xb8, 0x67, 0x28, 0x7a, 0x76, 0x19, 0x90, 0xd7, 0x13, 0x59, 0x63, 0xee, 0x0a, 0x7d, 0x59, 0xdc, 0xa5, 0xbb, 0x70, 0x47, 0x86, 0xbe, 0x79, 0xfc, 0x47, 0x6f, 0x91, 0xd3, 0xf3, 0xf8, 0x9b, 0x03, 0x98, 0x4d, 0x80, 0x68, 0xdc, 0xf1, 0xbb, 0x7d, 0xfc, 0x66, 0x37, 0xb4, 0x54, 0x50, 0xac, 0x04]),
+            verified: false,
+        }
+    ]
+};
diff --git a/test/fixtures/wpt/common/META.yml b/test/fixtures/wpt/common/META.yml
index ca4d2e523c08662..963dff9d1f1ecfb 100644
--- a/test/fixtures/wpt/common/META.yml
+++ b/test/fixtures/wpt/common/META.yml
@@ -1,3 +1,2 @@
 suggested_reviewers:
-  - zqzhang
   - deniak
diff --git a/test/fixtures/wpt/common/dispatcher/dispatcher.js b/test/fixtures/wpt/common/dispatcher/dispatcher.js
index a0f9f43e622483c..dab0100020b8291 100644
--- a/test/fixtures/wpt/common/dispatcher/dispatcher.js
+++ b/test/fixtures/wpt/common/dispatcher/dispatcher.js
@@ -1,7 +1,32 @@
 // Define a universal message passing API. It works cross-origin and across
 // browsing context groups.
 const dispatcher_path = "/common/dispatcher/dispatcher.py";
-const dispatcher_url = new URL(dispatcher_path, location.href).href;
+
+// Finds the nearest ancestor window that has a non srcdoc location. This should
+// give us a usable location for constructing further URLs.
+function findLocationFromAncestors(w) {
+  if (w.location.href == 'about:srcdoc') {
+    return findLocationFromAncestors(w.parent);
+  }
+  return w.location;
+}
+
+// Handles differences between workers vs frames (src vs srcdoc).
+function findLocation() {
+  if (location.href == 'about:srcdoc') {
+    return findLocationFromAncestors(window.parent);
+  }
+  if (location.protocol == 'blob:' || location.protocol == 'data:') {
+    // Allows working around blob and data URLs.
+    if (self.document && self.document.baseURI) {
+      return self.document.baseURI;
+    }
+  }
+  return location;
+}
+
+const dispatcherLocation = findLocation();
+const dispatcher_url = new URL(dispatcher_path, dispatcherLocation).href;
 
 // Return a promise, limiting the number of concurrent accesses to a shared
 // resources to |max_concurrent_access|.
@@ -138,7 +163,7 @@ const cacheableShowRequestHeaders = function(origin, uuid) {
 //   protocol: (optional) Sets the returned URL's `protocol` property.
 // }
 function remoteExecutorUrl(uuid, options) {
-  const url = new URL("/common/dispatcher/remote-executor.html", location);
+  const url = new URL("/common/dispatcher/remote-executor.html", dispatcherLocation);
   url.searchParams.set("uuid", uuid);
 
   if (options?.host) {
diff --git a/test/fixtures/wpt/common/dummy.json b/test/fixtures/wpt/common/dummy.json
new file mode 100644
index 000000000000000..0967ef424bce679
--- /dev/null
+++ b/test/fixtures/wpt/common/dummy.json
@@ -0,0 +1 @@
+{}
diff --git a/test/fixtures/wpt/common/media.js b/test/fixtures/wpt/common/media.js
index f2dc86126604954..a5a8e957e9b5be6 100644
--- a/test/fixtures/wpt/common/media.js
+++ b/test/fixtures/wpt/common/media.js
@@ -9,10 +9,12 @@ function getVideoURI(base)
 
     var videotag = document.createElement("video");
 
-    if ( videotag.canPlayType  &&
-         videotag.canPlayType('video/ogg; codecs="theora, vorbis"') )
+    if ( videotag.canPlayType )
     {
-        extension = '.ogv';
+      if (videotag.canPlayType('video/webm; codecs="vp9, opus"') )
+      {
+          extension = '.webm';
+      }
     }
 
     return base + extension;
@@ -46,10 +48,10 @@ function getAudioURI(base)
 function getMediaContentType(url) {
     var extension = new URL(url, location).pathname.split(".").pop();
     var map = {
-        "mp4": "video/mp4",
-        "ogv": "application/ogg",
-        "mp3": "audio/mp3",
-        "oga": "application/ogg",
+        "mp4" : "video/mp4",
+        "webm": "video/webm",
+        "mp3" : "audio/mp3",
+        "oga" : "application/ogg",
     };
     return map[extension];
 }
diff --git a/test/fixtures/wpt/common/top-layer.js b/test/fixtures/wpt/common/top-layer.js
new file mode 100644
index 000000000000000..2dc8ce3893aa721
--- /dev/null
+++ b/test/fixtures/wpt/common/top-layer.js
@@ -0,0 +1,29 @@
+// This function is a version of test_driver.bless which works while there are
+// elements in the top layer:
+// https://github.com/web-platform-tests/wpt/issues/41218.
+// Pass it the element at the top of the top layer stack.
+window.blessTopLayer = async (topLayerElement) => {
+  const button = document.createElement('button');
+  topLayerElement.append(button);
+  let wait_click = new Promise(resolve => button.addEventListener("click", resolve, {once: true}));
+  await test_driver.click(button);
+  await wait_click;
+  button.remove();
+};
+
+window.isTopLayer = (el) => {
+  // A bit of a hack. Just test a few properties of the ::backdrop pseudo
+  // element that change when in the top layer.
+  const properties = ['right','background'];
+  const testEl = document.createElement('div');
+  document.body.appendChild(testEl);
+  const computedStyle = getComputedStyle(testEl, '::backdrop');
+  const nonTopLayerValues = properties.map(p => computedStyle[p]);
+  testEl.remove();
+  for(let i=0;i<properties.length;++i) {
+    if (getComputedStyle(el,'::backdrop')[properties[i]] !== nonTopLayerValues[i]) {
+      return true;
+    }
+  }
+  return false;
+};
diff --git a/test/fixtures/wpt/compression/decompression-buffersource.tentative.any.js b/test/fixtures/wpt/compression/decompression-buffersource.tentative.any.js
index abb51751c8b4a3f..f4316ba1fc876ec 100644
--- a/test/fixtures/wpt/compression/decompression-buffersource.tentative.any.js
+++ b/test/fixtures/wpt/compression/decompression-buffersource.tentative.any.js
@@ -49,7 +49,7 @@ const bufferSourceChunksForDeflate = [
   },
   {
     name: 'Float16Array',
-    value: new Float16Array(new Uint8Array(compressedBytesWithDeflate).buffer)
+    value: () => new Float16Array(new Uint8Array(compressedBytesWithDeflate).buffer)
   },
   {
     name: 'Float32Array',
@@ -100,7 +100,7 @@ const bufferSourceChunksForGzip = [
   },
   {
     name: 'Float16Array',
-    value: new Float16Array(new Uint8Array(compressedBytesWithGzip).buffer)
+    value: () => new Float16Array(new Uint8Array(compressedBytesWithGzip).buffer)
   },
   {
     name: 'Float32Array',
@@ -151,7 +151,7 @@ const bufferSourceChunksForDeflateRaw = [
   },
   {
     name: 'Float16Array',
-    value: new Float16Array(new Uint8Array(compressedBytesWithDeflateRaw).buffer)
+    value: () => new Float16Array(new Uint8Array(compressedBytesWithDeflateRaw).buffer)
   },
   {
     name: 'Float32Array',
@@ -172,7 +172,7 @@ for (const chunk of bufferSourceChunksForDeflate) {
     const ds = new DecompressionStream('deflate');
     const reader = ds.readable.getReader();
     const writer = ds.writable.getWriter();
-    const writePromise = writer.write(chunk.value);
+    const writePromise = writer.write(typeof chunk.value === 'function' ? chunk.value() : chunk.value);
     writer.close();
     const { value } = await reader.read();
     assert_array_equals(Array.from(value), deflateExpectedChunkValue, 'value should match');
@@ -184,7 +184,7 @@ for (const chunk of bufferSourceChunksForGzip) {
     const ds = new DecompressionStream('gzip');
     const reader = ds.readable.getReader();
     const writer = ds.writable.getWriter();
-    const writePromise = writer.write(chunk.value);
+    const writePromise = writer.write(typeof chunk.value === 'function' ? chunk.value() : chunk.value);
     writer.close();
     const { value } = await reader.read();
     assert_array_equals(Array.from(value), gzipExpectedChunkValue, 'value should match');
@@ -196,7 +196,7 @@ for (const chunk of bufferSourceChunksForDeflateRaw) {
     const ds = new DecompressionStream('deflate-raw');
     const reader = ds.readable.getReader();
     const writer = ds.writable.getWriter();
-    const writePromise = writer.write(chunk.value);
+    const writePromise = writer.write(typeof chunk.value === 'function' ? chunk.value() : chunk.value);
     writer.close();
     const { value } = await reader.read();
     assert_array_equals(Array.from(value), deflateRawExpectedChunkValue, 'value should match');
diff --git a/test/fixtures/wpt/console/console-countReset-logging-manual.html b/test/fixtures/wpt/console/console-countReset-logging-manual.html
index 7fe01f50edbfa18..f0a9358fba5d74b 100644
--- a/test/fixtures/wpt/console/console-countReset-logging-manual.html
+++ b/test/fixtures/wpt/console/console-countReset-logging-manual.html
@@ -24,21 +24,25 @@
 console.count();
 console.countReset();
 console.count();
+console.countReset();
 
 console.count(undefined);
 console.countReset(undefined);
 console.count(undefined);
+console.countReset(undefined);
 
 console.count("default");
 console.countReset("default");
 console.count("default");
+console.countReset("default");
 
 console.count({toString() {return "default"}});
 console.countReset({toString() {return "default"}});
 console.count({toString() {return "default"}});
+console.countReset({toString() {return "default"}});
 
 console.count("a label");
-console.countReset();
+console.countReset("a label");
 console.count("a label");
 
 console.countReset("b"); // should produce a warning
diff --git a/test/fixtures/wpt/console/console-log-large-array.any.js b/test/fixtures/wpt/console/console-log-large-array.any.js
new file mode 100644
index 000000000000000..e5cb92d9d36d4ae
--- /dev/null
+++ b/test/fixtures/wpt/console/console-log-large-array.any.js
@@ -0,0 +1,8 @@
+// META: global=window,dedicatedworker,shadowrealm
+"use strict";
+// https://console.spec.whatwg.org/
+
+test(() => {
+    console.log(new Array(10000000).fill("x"));
+    console.log(new Uint8Array(10000000));
+}, "Logging large arrays works");
diff --git a/test/fixtures/wpt/console/console-log-symbol.any.js b/test/fixtures/wpt/console/console-log-symbol.any.js
new file mode 100644
index 000000000000000..a2facb6c64e8642
--- /dev/null
+++ b/test/fixtures/wpt/console/console-log-symbol.any.js
@@ -0,0 +1,10 @@
+// META: global=window,dedicatedworker,shadowrealm
+"use strict";
+// https://console.spec.whatwg.org/
+
+test(() => {
+    console.log(Symbol());
+    console.log(Symbol("abc"));
+    console.log(Symbol.for("def"));
+    console.log(Symbol.isConcatSpreadable);
+}, "Logging a symbol doesn't throw");
diff --git a/test/fixtures/wpt/dom/abort/WEB_FEATURES.yml b/test/fixtures/wpt/dom/abort/WEB_FEATURES.yml
new file mode 100644
index 000000000000000..d2fdc1555e28305
--- /dev/null
+++ b/test/fixtures/wpt/dom/abort/WEB_FEATURES.yml
@@ -0,0 +1,6 @@
+features:
+- name: aborting
+  files: "**"
+- name: abortsignal-any
+  files:
+  - abort-signal-any.any.js
diff --git a/test/fixtures/wpt/dom/abort/abort-signal-any-crash.html b/test/fixtures/wpt/dom/abort/abort-signal-any-crash.html
new file mode 100644
index 000000000000000..912c0d0ada73859
--- /dev/null
+++ b/test/fixtures/wpt/dom/abort/abort-signal-any-crash.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html class=test-wait>
+  <head>
+    <title>AbortSignal::Any when source signal was garbage collected</title>
+    <link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1908466">
+    <link rel="author" title="Vincent Hilla" href="mailto:vhilla@mozilla.com">
+    <script src="/common/gc.js"></script>
+  </head>
+  <body>
+    <p>Test passes if the browser does not crash.</p>
+    <script>
+        async function test() {
+            let controller = new AbortController();
+            let signal = AbortSignal.any([controller.signal]);
+            controller = undefined;
+            await garbageCollect();
+            AbortSignal.any([signal]);
+            document.documentElement.classList.remove('test-wait');
+        }
+        test();
+    </script>
+  </body>
+</html>
diff --git a/test/fixtures/wpt/dom/abort/resources/abort-signal-any-tests.js b/test/fixtures/wpt/dom/abort/resources/abort-signal-any-tests.js
index 66e4141eaccb08e..929ee8a2e61ab44 100644
--- a/test/fixtures/wpt/dom/abort/resources/abort-signal-any-tests.js
+++ b/test/fixtures/wpt/dom/abort/resources/abort-signal-any-tests.js
@@ -182,4 +182,43 @@ function abortSignalAnyTests(signalInterface, controllerInterface) {
     controller.abort();
     assert_equals(result, "01234");
   }, `Abort events for ${desc} signals fire in the right order ${suffix}`);
+
+  test(t => {
+    const controller = new controllerInterface();
+    const signal1 = signalInterface.any([controller.signal]);
+    const signal2 = signalInterface.any([signal1]);
+    let eventFired = false;
+
+    controller.signal.addEventListener('abort', () => {
+      const signal3 = signalInterface.any([signal2]);
+      assert_true(controller.signal.aborted);
+      assert_true(signal1.aborted);
+      assert_true(signal2.aborted);
+      assert_true(signal3.aborted);
+      eventFired = true;
+    });
+
+    controller.abort();
+    assert_true(eventFired, "event fired");
+  }, `Dependent signals for ${desc} are marked aborted before abort events fire ${suffix}`);
+
+  test(t => {
+    const controller1 = new controllerInterface();
+    const controller2 = new controllerInterface();
+    const signal = signalInterface.any([controller1.signal, controller2.signal]);
+    let count = 0;
+
+    controller1.signal.addEventListener('abort', () => {
+      controller2.abort("reason 2");
+    });
+
+    signal.addEventListener('abort', () => {
+      count++;
+    });
+
+    controller1.abort("reason 1");
+    assert_equals(count, 1);
+    assert_true(signal.aborted);
+    assert_equals(signal.reason, "reason 1");
+  }, `Dependent signals for ${desc} are aborted correctly for reentrant aborts ${suffix}`);
 }
diff --git a/test/fixtures/wpt/dom/events/Event-dispatch-click.html b/test/fixtures/wpt/dom/events/Event-dispatch-click.html
index 010305775df7e98..ab4a24a5ad50964 100644
--- a/test/fixtures/wpt/dom/events/Event-dispatch-click.html
+++ b/test/fixtures/wpt/dom/events/Event-dispatch-click.html
@@ -87,6 +87,22 @@
   child.dispatchEvent(new MouseEvent("click", {bubbles:true}))
 }, "pick the first with activation behavior <a href>")
 
+async_test(function(t) {
+  var input = document.createElement("input")
+  input.type = "radio"
+  dump.appendChild(input)
+  input.onclick = t.step_func(function() {
+    assert_false(input.checked, "input pre-click must not be triggered")
+  })
+  var child = input.appendChild(document.createElement("input"))
+  child.type = "radio"
+  child.onclick = t.step_func(function() {
+    assert_true(child.checked, "child pre-click must be triggered")
+  })
+  child.dispatchEvent(new MouseEvent("click", {bubbles:true}))
+  t.done()
+}, "pick the first with activation behavior <input type=radio>")
+
 async_test(function(t) {
   var input = document.createElement("input")
   input.type = "checkbox"
@@ -173,6 +189,46 @@
   t.done()
 }, "disabled checkbox still has activation behavior, part 2")
 
+async_test(function(t) {
+  var state = "start"
+
+  var form = document.createElement("form")
+  form.onsubmit = t.step_func(() => {
+    if(state == "start" || state == "radio") {
+      state = "failure"
+    } else if(state == "form") {
+      state = "done"
+    }
+    return false
+  })
+  dump.appendChild(form)
+  var button = form.appendChild(document.createElement("button"))
+  button.type = "submit"
+  var radio = button.appendChild(document.createElement("input"))
+  radio.type = "radio"
+  radio.onclick = t.step_func(() => {
+    if(state == "start") {
+      assert_unreached()
+    } else if(state == "radio") {
+      assert_true(radio.checked)
+    }
+  })
+  radio.disabled = true
+  radio.click()
+  assert_equals(state, "start")
+
+  state = "radio"
+  radio.disabled = false
+  radio.click()
+  assert_equals(state, "radio")
+
+  state = "form"
+  button.click()
+  assert_equals(state, "done")
+
+  t.done()
+}, "disabled radio still has activation behavior")
+
 async_test(function(t) {
   var input = document.createElement("input")
   input.type = "checkbox"
diff --git a/test/fixtures/wpt/dom/events/Event-dispatch-on-disabled-elements.html b/test/fixtures/wpt/dom/events/Event-dispatch-on-disabled-elements.html
index 361006a7240496e..e7d6b455bbcaab8 100644
--- a/test/fixtures/wpt/dom/events/Event-dispatch-on-disabled-elements.html
+++ b/test/fixtures/wpt/dom/events/Event-dispatch-on-disabled-elements.html
@@ -19,7 +19,7 @@
 <body>
 <script>
 // HTML elements that can be disabled
-const formElements = ["button", "fieldset", "input", "select", "textarea"];
+const formElements = ["button", "input", "select", "textarea"];
 
 test(() => {
   for (const localName of formElements) {
diff --git a/test/fixtures/wpt/dom/events/Event-dispatch-single-activation-behavior.html b/test/fixtures/wpt/dom/events/Event-dispatch-single-activation-behavior.html
new file mode 100644
index 000000000000000..2b6568a60af51f5
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/Event-dispatch-single-activation-behavior.html
@@ -0,0 +1,164 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title> Only one activation behavior is executed during dispatch</title>
+<link rel="author" title="Vincent Hilla" href="mailto:vhilla@mozilla.com">
+<link rel="help" href="https://dom.spec.whatwg.org/#eventtarget-activation-behavior">
+<link rel="help" href="https://dom.spec.whatwg.org/#concept-event-dispatch">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id=log></div>
+
+<div id=test_container></div>
+
+<!--
+    Three classes:
+    click
+        Element to be clicked to cause activation behavior
+    activates
+        Element that registers the activation behavior
+    container
+        Element in which other elements with activation behavior are placed.
+        We test that those won't be activated too.
+-->
+<template>
+    <!--input, change event bubble, so have to check if checked is true-->
+    <input class="click activates container" type="checkbox" oninput="this.checked ? activated(this) : null">
+    <input class="click activates container" type="radio" oninput="this.checked ? activated(this) : null">
+    <form onsubmit="activated(this); return false" class="activates">
+        <input class="click container" type="submit">
+    </form>
+    <form onsubmit="activated(this); return false" class="activates">
+        <input class="click container" type="image">
+    </form>
+    <form onreset="activated(this)" class="activates">
+        <input class="click container" type="reset">
+    </form>
+    <form onsubmit="activated(this); return false" class="activates">
+        <button class="click container" type="submit"></button>
+    </form>
+    <form onreset="activated(this)" class="activates">
+        <button class="click container" type="reset"></button>
+    </form>
+    <a href="#link" class="click container activates"></a>
+    <area href="#link" class="click container activates">
+    <details ontoggle="activated(this)" class="activates">
+        <summary class="click container"></summary>
+    </details>
+    <label>
+      <input type=checkbox onclick="this.checked ? activated(this) : null" class="activates">
+      <span class="click container">label</span>
+    </label>
+    <!--activation behavior of label for event targeted at interactive content descendant is to do nothing-->
+    <label class="container">
+        <button class="click" type="button"></button>
+    </label>
+</template>
+
+<script>
+let activations = [];
+function activated(e) {
+    activations.push(e);
+}
+
+function getActivations(testidx) {
+    return activations.filter(a =>
+        (a.endsWith && a.endsWith("test"+testidx+"_link"))
+        || (a.classList && a.classList.contains("test"+testidx))
+    );
+}
+
+// for a and area elements
+window.onhashchange = function(e) {
+    if (e.newURL.endsWith("link")) {
+        activated(e.newURL);
+    }
+    window.location.hash = "";
+};
+
+function getElementsByClassNameInclusive(e, clsname) {
+    let ls = Array.from(e.getElementsByClassName(clsname));
+    if (e.classList.contains(clsname)) ls.push(e);
+    return ls;
+}
+
+function getClickTarget(e) {
+    return getElementsByClassNameInclusive(e, "click")[0];
+}
+
+function getContainer(e) {
+    return getElementsByClassNameInclusive(e, "container")[0];
+}
+
+function getExpectedActivations(e) {
+    let ls = getElementsByClassNameInclusive(e, "activates");
+
+    // special case, for a and area the window registers the activation
+    // have to use string, as testrunner cannot stringify the window object
+    ls = ls.map(e => e.tagName === "A" || e.tagName === "AREA" ? e.href : e);
+
+    return ls;
+}
+
+function toString(e) {
+    const children = Array.from(e.children);
+    const childstr = (children.map(toString)).join("");
+    const tag = e.tagName;
+    const typestr = e.type ? " type="+e.type : "";
+    return `<${tag}${typestr}>${childstr}</${tag}>`;
+}
+
+// generate O(n^2) test combinations
+const template = document.querySelector("template");
+const elements = Array.from(template.content.children);
+const tests = []
+for (const target of elements) {
+    for (const parent of elements) {
+        if (target === parent) continue;
+        tests.push([target.cloneNode(true), parent.cloneNode(true)])
+    }
+}
+
+const test_container = document.getElementById("test_container");
+
+/**
+ * Test that if two elements in an event target chain have activation behavior,
+ * only one of them will be activated.
+ *
+ * Each child of <template> represents one case of activation behavior.
+ * The behavior should be triggered by clicking the element of class click
+ * and will manifest as a call to activated().
+ *
+ * For each [target, parent] in tests, we make target a descendant of parent
+ * and test that only target gets activated when dispatching a click.
+ */
+for (let i = 0; i < tests.length; i++) {
+    let [target, parent] = tests[i];
+    async_test(function(t) {
+        let test = document.createElement("div");
+        test_container.appendChild(test);
+        test.appendChild(parent);
+        getContainer(parent).appendChild(target);
+
+        // for later filtering out the activations belonging to this test
+        for (let e of test.getElementsByClassName("activates")) {
+            e.classList.add("test"+i);
+        }
+        for (let e of test.querySelectorAll("a, area")) {
+            e.href = "#test"+i+"_link";
+        }
+
+        getClickTarget(target).click();
+
+        // Need to spin event loop twice, as some clicks might dispatch another task
+        t.step_timeout(() => {
+            t.step_timeout(t.step_func_done(() => {
+                    assert_array_equals(getActivations(i), getExpectedActivations(target));
+            }), 0);
+        }, 0);
+
+        t.add_cleanup(function() {
+            test_container.removeChild(test);
+        });
+    }, `When clicking child ${toString(target)} of parent ${toString(parent)}, only child should be activated.`);
+}
+</script>
diff --git a/test/fixtures/wpt/dom/events/Event-dispatch-throwing-multiple-globals.html b/test/fixtures/wpt/dom/events/Event-dispatch-throwing-multiple-globals.html
new file mode 100644
index 000000000000000..a56fdf6af865812
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/Event-dispatch-throwing-multiple-globals.html
@@ -0,0 +1,69 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<body>
+<script>
+function createIframe(t, srcdoc = '') {
+  let iframe = document.createElement('iframe');
+  iframe.srcdoc = srcdoc;
+  t.add_cleanup(() => iframe.remove());
+  return new Promise((resolve, reject) => {
+    iframe.addEventListener('load', () => resolve(iframe.contentWindow));
+    document.body.appendChild(iframe);
+  });
+}
+
+// Returns a promise which will resolve with the next error event fired at any
+// of `windows`, after the invocation of this function. Once one does, this
+// function removes its listeners and produces that error event so that it can
+// be examined (most notably for which global proxy it was targeted at).
+async function nextErrorEvent(windows) {
+  let listener;
+  let p = new Promise((resolve, reject) => {
+    listener = (event) => { resolve(event); event.preventDefault(); };
+  });
+  for (let w of windows) {
+    w.addEventListener('error', listener);
+  }
+  try {
+    return await p;
+  } finally {
+    for (let w of windows) {
+      w.removeEventListener('error', listener);
+    }
+  }
+}
+
+promise_test(async t => {
+  let w = await createIframe(t, `<script>function listener() { throw new Error(); }<`+`/script>`);
+  let w2 = await createIframe(t);
+
+  let target = new w2.EventTarget();
+  target.addEventListener('party', w.listener);
+  let nextErrorPromise = nextErrorEvent([self, w, w2]);
+  target.dispatchEvent(new Event('party'));
+  let errorEvent = await nextErrorPromise;
+  if (errorEvent.error) {
+    assert_true(errorEvent.error instanceof w.Error, 'error should be an instance created inside the listener function');
+  }
+  assert_equals(errorEvent.target, w, `error event should target listener's global but instead targets ${event.currentTarget === w2 ? 'target\'s global' : 'test harness global'}`);
+}, 'exception thrown in event listener function should result in error event on listener\'s global');
+
+promise_test(async t => {
+  let w = await createIframe(t, `<script>listener = {};<`+`/script>`);
+  let w2 = await createIframe(t, `<script>handleEvent = () => { throw new Error; };<`+`/script>`);
+  let w3 = await createIframe(t);
+  w.listener.handleEvent = w2.handleEvent;
+
+  let target = new w3.EventTarget();
+  target.addEventListener('party', w.listener);
+  let nextErrorPromise = nextErrorEvent([self, w, w2, w3]);
+  target.dispatchEvent(new Event('party'));
+  let errorEvent = await nextErrorPromise;
+  if (errorEvent.error) {
+    assert_true(errorEvent.error instanceof w2.Error, 'error should be an instance created inside the listener function');
+  }
+  assert_equals(errorEvent.target, w, `error event should target listener's global but instead targets ${event.currentTarget === w2 ? 'target\'s global' : event.currentTarget === w3 ? 'function\'s global' : 'test harness global'}`);
+}, 'exception thrown in event listener interface object should result in error event on listener\'s global');
+</script>
+</body>
diff --git a/test/fixtures/wpt/dom/events/EventTarget-constructible.any.js b/test/fixtures/wpt/dom/events/EventTarget-constructible.any.js
index b0e7614e625b3de..4125d23f0c96506 100644
--- a/test/fixtures/wpt/dom/events/EventTarget-constructible.any.js
+++ b/test/fixtures/wpt/dom/events/EventTarget-constructible.any.js
@@ -23,6 +23,23 @@ test(() => {
   assert_equals(callCount, 2);
 }, "A constructed EventTarget can be used as expected");
 
+test(() => {
+  const target = new EventTarget();
+  const event = new Event("foo");
+
+  function listener(e) {
+    assert_equals(e, event);
+    assert_equals(e.target, target);
+    assert_equals(e.currentTarget, target);
+    assert_array_equals(e.composedPath(), [target]);
+  }
+  target.addEventListener("foo", listener, { once: true });
+  target.dispatchEvent(event);
+  assert_equals(event.target, target);
+  assert_equals(event.currentTarget, null);
+  assert_array_equals(event.composedPath(), []);
+}, "A constructed EventTarget implements dispatch correctly");
+
 test(() => {
   class NicerEventTarget extends EventTarget {
     on(...args) {
diff --git a/test/fixtures/wpt/dom/events/event-global.html b/test/fixtures/wpt/dom/events/event-global.html
index 3e8d25ecb5dd9d8..f70606fb65496a6 100644
--- a/test/fixtures/wpt/dom/events/event-global.html
+++ b/test/fixtures/wpt/dom/events/event-global.html
@@ -114,4 +114,14 @@
 
   target.dispatchEvent(new Event("click"));
 }, "window.event is set to the current event, which is the event passed to dispatch");
+
+async_test(t => {
+  let target = new XMLHttpRequest();
+
+  target.onload = t.step_func_done(e => {
+    assert_equals(e, window.event);
+  });
+
+  target.dispatchEvent(new Event("load"));
+}, "window.event is set to the current event, which is the event passed to dispatch (2)");
 </script>
diff --git a/test/fixtures/wpt/dom/events/pointer-event-document-move.html b/test/fixtures/wpt/dom/events/pointer-event-document-move.html
new file mode 100644
index 000000000000000..91e7c36860572a7
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/pointer-event-document-move.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<link rel="help" href="https://crbug.com/341104769">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+
+<template>
+  <p>TEST</p>
+</template>
+
+<body>
+<script>
+  const clone = document.querySelector("template").content.cloneNode(true);
+  const p = clone.querySelector("p");
+
+  let gotEvent = false;
+  p.addEventListener("pointerup", () => {
+    gotEvent = true;
+  });
+
+  document.body.append(clone);
+
+  promise_test(async () => {
+    await test_driver.click(document.querySelector("p"));
+    assert_true(gotEvent);
+  }, "Moving a node to new document should move the registered event listeners together");
+</script>
diff --git a/test/fixtures/wpt/dom/events/preventDefault-during-activation-behavior.html b/test/fixtures/wpt/dom/events/preventDefault-during-activation-behavior.html
new file mode 100644
index 000000000000000..928740313471656
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/preventDefault-during-activation-behavior.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<title>preventDefault during activation behavior</title>
+<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=1197032">
+<link rel="help" href="https://html.spec.whatwg.org/multipage/C#the-button-element">
+<link rel="help" href="https://dom.spec.whatwg.org/#dispatching-events">
+<link rel="author" title="L. David Baron" href="https://dbaron.org/">
+<link rel="author" title="Google" href="http://www.google.com/">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<body>
+
+<form id="f">
+  <input type="submit" id="b">
+</form>
+
+<script>
+
+promise_test(async () => {
+  let form = document.getElementById("f");
+  let button = document.getElementById("b");
+
+  let cached_event;
+  let submit_fired = false;
+
+  let click_promise = new Promise((resolve, reject) => {
+    button.addEventListener("click", event => {
+      assert_false(submit_fired);
+      cached_event = event;
+      resolve();
+    });
+  });
+
+  form.addEventListener("submit", event => {
+    assert_false(submit_fired);
+    assert_true(!!cached_event, "click should have fired");
+
+    // Call preventDefault on the click event during its activation
+    // behavior, to test the bug that we're trying to test.
+    cached_event.preventDefault();
+
+    // prevent the form submission from navigating the page
+    event.preventDefault();
+
+    submit_fired = true;
+  });
+
+  assert_false(submit_fired);
+  button.click();
+  await click_promise;
+  assert_true(submit_fired);
+}, "behavior of preventDefault during activation behavior");
+
+</script>
diff --git a/test/fixtures/wpt/dom/events/remove-all-listeners.html b/test/fixtures/wpt/dom/events/remove-all-listeners.html
new file mode 100644
index 000000000000000..3a2a751a146bca0
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/remove-all-listeners.html
@@ -0,0 +1,95 @@
+<!doctype html>
+<title>Various edge cases where listeners are removed during iteration</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="log"></div>
+<script>
+
+test(function() {
+  var type = "foo";
+  var target = document.createElement("div");
+
+  var listener1CallCount = 0;
+  var listener2CallCount = 0;
+  var listener3CallCount = 0;
+  function listener1() {
+    listener1CallCount++;
+    target.removeEventListener(type, listener1);
+    target.removeEventListener(type, listener2);
+    target.addEventListener(type, listener3);
+  }
+  function listener2() {
+    listener2CallCount++;
+  }
+  function listener3() {
+    listener3CallCount++;
+  }
+
+  target.addEventListener(type, listener1);
+  target.addEventListener(type, listener2);
+
+  // Dispatch the event. Only listener1 should be called because
+  // it removes listener2. And listener3 is added when we've already
+  // started iterating, so it shouldn't be called either.
+  target.dispatchEvent(new Event(type));
+  assert_equals(listener1CallCount, 1);
+  assert_equals(listener2CallCount, 0);
+  assert_equals(listener3CallCount, 0);
+
+  // Now that only listener3 is set, dispatch another event. Only
+  // listener3 should be called.
+  target.dispatchEvent(new Event(type));
+  assert_equals(listener1CallCount, 1);
+  assert_equals(listener2CallCount, 0);
+  assert_equals(listener3CallCount, 1);
+}, "Removing all listeners and then adding a new one should work.");
+
+test(function() {
+  var type = "foo";
+  var target = document.createElement("div");
+
+  var listener1CallCount = 0;
+  var listener2CallCount = 0;
+  var listener3CallCount = 0;
+  function listener1() {
+    listener1CallCount++;
+    // Recursively dispatch another event from this listener.
+    // This will only call listener2 because listener1 is a "once" listener.
+    target.dispatchEvent(new Event(type));
+    assert_equals(listener1CallCount, 1);
+    assert_equals(listener2CallCount, 1);
+    assert_equals(listener3CallCount, 0);
+
+    // Now all listeners are removed - the two "once" listeners have already both
+    // been called once. Add another listener.
+    target.addEventListener(type, listener3);
+  }
+  function listener2() {
+    listener2CallCount++;
+  }
+  function listener3() {
+    listener3CallCount++;
+  }
+
+  // Add two "once" listeners.
+  target.addEventListener(type, listener1, { once: true });
+  target.addEventListener(type, listener2, { once: true });
+
+  // Dispatch the event.
+  target.dispatchEvent(new Event(type));
+
+  // The listener call counts should still match what they were
+  // at the end of listener1.
+  assert_equals(listener1CallCount, 1);
+  assert_equals(listener2CallCount, 1);
+  assert_equals(listener3CallCount, 0);
+
+  // Now that only listener3 is set, dispatch another event. Only
+  // listener3 should be called.
+  target.dispatchEvent(new Event(type));
+  assert_equals(listener1CallCount, 1);
+  assert_equals(listener2CallCount, 1);
+  assert_equals(listener3CallCount, 1);
+}, "Nested usage of once listeners should work.");
+
+</script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/WEB_FEATURES.yml b/test/fixtures/wpt/dom/events/scrolling/WEB_FEATURES.yml
new file mode 100644
index 000000000000000..e4fba841b62ac94
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/WEB_FEATURES.yml
@@ -0,0 +1,4 @@
+features:
+- name: scrollend
+  files:
+  - scrollend-*
diff --git a/test/fixtures/wpt/dom/events/scrolling/overscroll-deltas.html b/test/fixtures/wpt/dom/events/scrolling/overscroll-deltas.html
index 6f0b77f22eda2ab..e13e9f1cce5949d 100644
--- a/test/fixtures/wpt/dom/events/scrolling/overscroll-deltas.html
+++ b/test/fixtures/wpt/dom/events/scrolling/overscroll-deltas.html
@@ -6,80 +6,152 @@
 <script src="/resources/testdriver-vendor.js"></script>
 <script src="scroll_support.js"></script>
 <style>
-#targetDiv {
-  width: 500px;
-  height: 500px;
-  background: red;
-}
-html, body {
-  /* Prevent any built-in browser overscroll features from consuming the scroll
-   * deltas */
-  overscroll-behavior: none;
-}
+  #hspacer {
+    height: 100px;
+    width: 100vw;
+    top: 0;
+    /* on the right edge of targetDiv */
+    left: 200px;
+    position: absolute;
+  }
 
+  #vspacer {
+    height: 100vh;
+    width: 100px;
+    position: absolute;
+  }
+
+  #targetDiv {
+    width: 200px;
+    height: 200px;
+    overflow: scroll;
+  }
+
+  #innerDiv {
+    width: 400px;
+    height: 400px;
+  }
 </style>
 
-<body style="margin:0;" onload=runTest()>
-<div id="targetDiv">
-</div>
+<body style="margin:0" onload=runTest()>
+  <div id="targetDiv">
+    <div id="innerDiv"></div>
+  </div>
+  <div id="hspacer"></div>
+  <div id="vspacer"></div>
 </body>
 
 <script>
-var target_div = document.getElementById('targetDiv');
-var overscrolled_x_deltas = [];
-var overscrolled_y_deltas = [];
-var scrollend_received = false;
-
-function onOverscroll(event) {
-  overscrolled_x_deltas.push(event.deltaX);
-  overscrolled_y_deltas.push(event.deltaY);
-}
-
-function onScrollend(event) {
-  scrollend_received = true;
-}
-
-document.addEventListener("overscroll", onOverscroll);
-document.addEventListener("scrollend", onScrollend);
-
-function runTest() {
-  promise_test (async (t) => {
-    await waitForCompositorCommit();
-
-    // Scroll up on target div and wait for the doc to get overscroll event.
-    await touchScrollInTarget(300, target_div, 'up');
-    await waitFor(() => { return scrollend_received; },
-        'Document did not receive scrollend event.');
-
-    // Even though we request 300 pixels of scroll, the API above doesn't
-    // guarantee how much scroll delta will be generated - different browsers
-    // can consume different amounts for "touch slop" (for example). Ensure the
-    // overscroll reaches at least 100 pixels which is a fairly conservative
-    // value.
-    assert_greater_than(overscrolled_y_deltas.length, 0, "There should be at least one overscroll events when overscrolling.");
-    assert_equals(overscrolled_x_deltas.filter(function(x){ return x!=0; }).length, 0, "The deltaX attribute must be 0 when there is no scrolling in x direction.");
-    assert_less_than_equal(Math.max(...overscrolled_y_deltas), 0, "The deltaY attribute must be <= 0 when there is overscrolling in up direction.");
-    assert_less_than_equal(Math.min(...overscrolled_y_deltas),-100, "The deltaY attribute must be the number of pixels overscrolled.");
-
-    await waitForCompositorCommit();
+  var target_div = document.getElementById('targetDiv');
+  var overscrolled_x_deltas = [];
+  var overscrolled_y_deltas = [];
+  var scrollend_received = false;
+
+  function onOverscroll(event) {
+    overscrolled_x_deltas.push(event.deltaX);
+    overscrolled_y_deltas.push(event.deltaY);
+  }
+
+  async function resetScrollers(test) {
+    await waitForScrollReset(test, target_div);
+    await waitForScrollReset(test, document.scrollingElement);
+  }
+
+  function resetOverScrollDeltas() {
     overscrolled_x_deltas = [];
     overscrolled_y_deltas = [];
-    scrollend_received = false;
-
-    // Scroll left on target div and wait for the doc to get overscroll event.
-    await touchScrollInTarget(300, target_div, 'left');
-    await waitFor(() => { return scrollend_received; },
-        'Document did not receive scrollend event.');
-
-    // TODO(bokan): It looks like Chrome inappropriately filters some scroll
-    // events despite |overscroll-behavior| being set to none. The overscroll
-    // amount here has been loosened but this should be fixed in Chrome.
-    // https://crbug.com/1112183.
-    assert_greater_than(overscrolled_y_deltas.length, 0, "There should be at least one overscroll events when overscrolling.");
-    assert_equals(overscrolled_y_deltas.filter(function(x){ return x!=0; }).length, 0, "The deltaY attribute must be 0 when there is no scrolling in y direction.");
-    assert_less_than_equal(Math.max(...overscrolled_x_deltas), 0, "The deltaX attribute must be <= 0 when there is overscrolling in left direction.");
-    assert_less_than_equal(Math.min(...overscrolled_x_deltas),-50, "The deltaX attribute must be the number of pixels overscrolled.");
-
-  }, 'Tests that the document gets overscroll event with right deltaX/Y attributes.');
-}
+  }
+
+  function waitForOverscrollEventWithMinDelta(target, min_x = 0, min_y = 0) {
+    return new Promise((resolve) => {
+      target.addEventListener("overscroll", (evt) => {
+        if (evt.deltaX >= min_x && evt.deltaY >= min_y) {
+          resolve();
+        }
+      });
+    });
+  }
+
+  function unreachedScrollendListener() {
+    assert_unreached('Unexpected scrollend event');
+  }
+
+  document.addEventListener("overscroll", onOverscroll);
+
+  function runTest() {
+    promise_test(async (t) => {
+      await resetScrollers(t);
+      await waitForCompositorCommit();
+      resetOverScrollDeltas();
+
+      assert_equals(document.scrollingElement.scrollTop, 0,
+        "document should not be scrolled");
+
+      let scrollend_promise = waitForScrollendEvent(t, target_div);
+      let max_target_div_scroll_top = target_div.scrollHeight - target_div.clientHeight;
+      target_div.scrollTop = target_div.scrollHeight;
+      await scrollend_promise;
+      assert_equals(target_div.scrollTop, max_target_div_scroll_top,
+      "target_div should be fully scrolled down");
+
+      // Even though we request 300 extra pixels of scroll, the API above doesn't
+      // guarantee how much scroll delta will be generated - different browsers
+      // can consume different amounts for "touch slop" (for example). Ensure the
+      // overscroll reaches at least 250 pixels which is a fairly conservative
+      // value.
+      let overscroll_promise = waitForOverscrollEventWithMinDelta(document,
+          /*min_x*/0, /*min_y*/250);
+      scrollend_promise = waitForScrollendEvent(t, document, 2000);
+      target_div.addEventListener("scrollend", unreachedScrollendListener);
+      // Scroll target div vertically and wait for the doc to get scrollend event.
+      await scrollElementDown(target_div, target_div.clientHeight + 300);
+      await waitForCompositorCommit();
+      await overscroll_promise;
+      await scrollend_promise;
+
+      target_div.removeEventListener("scrollend", unreachedScrollendListener);
+      assert_greater_than(overscrolled_y_deltas.length, 0, "There should be at least one overscroll events when overscrolling.");
+      assert_equals(overscrolled_x_deltas.filter(function (x) { return x != 0; }).length, 0, "The deltaX attribute must be 0 when there is no scrolling in x direction.");
+      assert_less_than_equal(Math.max(...overscrolled_y_deltas), 300, "The deltaY attribute must be <= the number of pixels overscrolled (300)");
+      assert_greater_than(document.scrollingElement.scrollTop, target_div.clientHeight - 1,
+        "document is scrolled by the height of target_div");
+    }, "testing, vertical");
+
+    promise_test(async (t) => {
+      await resetScrollers(t);
+      await waitForCompositorCommit();
+      resetOverScrollDeltas();
+
+      assert_equals(document.scrollingElement.scrollLeft, 0,
+        "document should not be scrolled");
+
+      let scrollend_promise = waitForScrollendEvent(t, target_div);
+      let max_target_div_scroll_left = target_div.scrollWidth - target_div.clientWidth;
+      target_div.scrollLeft = target_div.scrollWidth;
+      await scrollend_promise;
+      assert_equals(target_div.scrollLeft, max_target_div_scroll_left,
+        "target_div should be fully scrolled right");
+
+      let overscroll_promise = waitForOverscrollEventWithMinDelta(document,
+          /*min_x*/250, /*min_y*/ 0);
+      scrollend_promise = waitForScrollendEvent(t, document, 2000);
+      target_div.addEventListener("scrollend", unreachedScrollendListener);
+      // Scroll target div horizontally and wait for the doc to get scrollend event.
+      await scrollElementLeft(target_div, target_div.clientWidth + 300);
+      await waitForCompositorCommit();
+      await overscroll_promise;
+      await scrollend_promise;
+
+      target_div.removeEventListener("scrollend", unreachedScrollendListener);
+      assert_greater_than(document.scrollingElement.scrollLeft, target_div.clientWidth - 1,
+        "document is scrolled by the height of target_div");
+      // TODO(bokan): It looks like Chrome inappropriately filters some scroll
+      // events despite |overscroll-behavior| being set to none. The overscroll
+      // amount here has been loosened but this should be fixed in Chrome.
+      // https://crbug.com/1112183.
+      assert_greater_than(overscrolled_x_deltas.length, 0, "There should be at least one overscroll events when overscrolling.");
+      assert_equals(overscrolled_y_deltas.filter(function(x){ return x!=0; }).length, 0, "The deltaY attribute must be 0 when there is no scrolling in y direction.");
+      assert_less_than_equal(Math.max(...overscrolled_x_deltas), 300, "The deltaX attribute must be <= number of pixels overscrolled (300)");
+    }, "testing, horizontal");
+  }
 </script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/overscroll-event-fired-to-scrolled-element.html b/test/fixtures/wpt/dom/events/scrolling/overscroll-event-fired-to-scrolled-element.html
index cfc782a809a7e73..be4176df59d6a1d 100644
--- a/test/fixtures/wpt/dom/events/scrolling/overscroll-event-fired-to-scrolled-element.html
+++ b/test/fixtures/wpt/dom/events/scrolling/overscroll-event-fired-to-scrolled-element.html
@@ -10,11 +10,14 @@
   width: 200px;
   height: 200px;
   overflow: scroll;
+  position: absolute;
+  left: 150px;
+  top: 150px;
 }
 
 #innerDiv {
-  width: 400px;
-  height: 400px;
+  width: 250px;
+  height: 250px;
 }
 </style>
 
@@ -45,7 +48,7 @@
     await waitForCompositorCommit();
 
     // Do a horizontal scroll and wait for overscroll event.
-    await touchScrollInTarget(300, scrolling_div , 'right');
+    await touchScrollInTarget(100, scrolling_div , 'right');
     await waitFor(() => { return overscrolled_x_delta > 0; },
         'Scroller did not receive overscroll event after horizontal scroll.');
     assert_equals(scrolling_div.scrollWidth - scrolling_div.scrollLeft,
@@ -55,7 +58,7 @@
     overscrolled_y_delta = 0;
 
     // Do a vertical scroll and wait for overscroll event.
-    await touchScrollInTarget(300, scrolling_div, 'down');
+    await touchScrollInTarget(100, scrolling_div, 'down');
     await waitFor(() => { return overscrolled_y_delta > 0; },
         'Scroller did not receive overscroll event after vertical scroll.');
     assert_equals(scrolling_div.scrollHeight - scrolling_div.scrollTop,
diff --git a/test/fixtures/wpt/dom/events/scrolling/scroll_support.js b/test/fixtures/wpt/dom/events/scrolling/scroll_support.js
index 169393e4c3e4194..a708364df07cada 100644
--- a/test/fixtures/wpt/dom/events/scrolling/scroll_support.js
+++ b/test/fixtures/wpt/dom/events/scrolling/scroll_support.js
@@ -1,15 +1,83 @@
-async function waitForScrollendEvent(test, target, timeoutMs = 500) {
+async function waitForEvent(eventName, test, target, timeoutMs = 500) {
   return new Promise((resolve, reject) => {
     const timeoutCallback = test.step_timeout(() => {
-      reject(`No Scrollend event received for target ${target}`);
+      reject(`No ${eventName} event received for target ${target}`);
     }, timeoutMs);
-    target.addEventListener('scrollend', (evt) => {
+    target.addEventListener(eventName, (evt) => {
       clearTimeout(timeoutCallback);
       resolve(evt);
     }, { once: true });
   });
 }
 
+async function waitForScrollendEvent(test, target, timeoutMs = 500) {
+  return waitForEvent("scrollend", test, target, timeoutMs);
+}
+
+async function waitForScrollendEventNoTimeout(target) {
+  return new Promise((resolve) => {
+    target.addEventListener("scrollend", resolve);
+  });
+}
+
+async function waitForPointercancelEvent(test, target, timeoutMs = 500) {
+  return waitForEvent("pointercancel", test, target, timeoutMs);
+}
+
+// Resets the scroll position to (0,0).  If a scroll is required, then the
+// promise is not resolved until the scrollend event is received.
+async function waitForScrollReset(test, scroller, x = 0, y = 0) {
+  return new Promise(resolve => {
+    if (scroller.scrollTop == x && scroller.scrollLeft == y) {
+      resolve();
+    } else {
+      const eventTarget =
+        scroller == document.scrollingElement ? document : scroller;
+      scroller.scrollTo(x, y);
+      waitForScrollendEventNoTimeout(eventTarget).then(resolve);
+    }
+  });
+}
+
+async function createScrollendPromiseForTarget(test,
+                                               target_div,
+                                               timeoutMs = 500) {
+  return waitForScrollendEvent(test, target_div, timeoutMs).then(evt => {
+    assert_false(evt.cancelable, 'Event is not cancelable');
+    assert_false(evt.bubbles, 'Event targeting element does not bubble');
+  });
+}
+
+function verifyNoScrollendOnDocument(test) {
+  const callback =
+      test.unreached_func("window got unexpected scrollend event.");
+  window.addEventListener('scrollend', callback);
+  test.add_cleanup(() => {
+    window.removeEventListener('scrollend', callback);
+  });
+}
+
+async function verifyScrollStopped(test, target_div) {
+  const unscaled_pause_time_in_ms = 100;
+  const x = target_div.scrollLeft;
+  const y = target_div.scrollTop;
+  return new Promise(resolve => {
+    test.step_timeout(() => {
+      assert_equals(target_div.scrollLeft, x);
+      assert_equals(target_div.scrollTop, y);
+      resolve();
+    }, unscaled_pause_time_in_ms);
+  });
+}
+
+async function resetTargetScrollState(test, target_div) {
+  if (target_div.scrollTop != 0 || target_div.scrollLeft != 0) {
+    target_div.scrollTop = 0;
+    target_div.scrollLeft = 0;
+    return waitForScrollendEvent(test, target_div);
+  }
+}
+
 const MAX_FRAME = 700;
 const MAX_UNCHANGED_FRAMES = 20;
 
@@ -45,6 +113,29 @@ function waitForCompositorCommit() {
   });
 }
 
+// Please don't remove this. This is necessary for chromium-based browsers. It
+// can be a no-op on user-agents that do not have a separate compositor thread.
+// TODO(crbug.com/1509054): This shouldn't be necessary if the test harness
+// deferred running the tests until after paint holding.
+async function waitForCompositorReady() {
+  const animation =
+      document.body.animate({ opacity: [ 0, 1 ] }, {duration: 1 });
+  return animation.finished;
+}
+
+function waitForNextFrame() {
+  const startTime = performance.now();
+  return new Promise(resolve => {
+    window.requestAnimationFrame((frameTime) => {
+      if (frameTime < startTime) {
+        window.requestAnimationFrame(resolve);
+      } else {
+        resolve();
+      }
+    });
+  });
+}
+
 // TODO(crbug.com/1400399): Deprecate as frame rates may vary greatly in
 // different test environments.
 function waitForAnimationEnd(getValue) {
@@ -70,6 +161,10 @@ function waitForAnimationEnd(getValue) {
 }
 
 // Scrolls in target according to move_path with pauses in between
+// The move_path should contains coordinates that are within target boundaries.
+// Keep in mind that 0,0 is the center of the target element and is also
+// the pointerDown position.
+// pointerUp() is fired after sequence of moves.
 function touchScrollInTargetSequentiallyWithPause(target, move_path, pause_time_in_ms = 100) {
   const test_driver_actions = new test_driver.Actions()
     .addPointer("pointer1", "touch")
@@ -88,7 +183,7 @@ function touchScrollInTargetSequentiallyWithPause(target, move_path, pause_time_
       y += step_y;
       test_driver_actions.pointerMove(x, y, {origin: target});
     }
-    test_driver_actions.pause(pause_time_in_ms);
+    test_driver_actions.pause(pause_time_in_ms); // To prevent inertial scroll
   }
 
   return test_driver_actions.pointerUp().send();
@@ -125,7 +220,7 @@ function touchScrollInTarget(pixels_to_scroll, target, direction, pause_time_in_
 
 // Trigger fling by doing pointerUp right after pointerMoves.
 function touchFlingInTarget(pixels_to_scroll, target, direction) {
-  touchScrollInTarget(pixels_to_scroll, target, direction, 0 /* pause_time */);
+  return touchScrollInTarget(pixels_to_scroll, target, direction, 0 /* pause_time */);
 }
 
 function mouseActionsInTarget(target, origin, delta, pause_time_in_ms = 100) {
@@ -161,3 +256,23 @@ function conditionHolds(condition, error_message = 'Condition is not true anymor
     tick(0);
   });
 }
+
+function scrollElementDown(element, scroll_amount) {
+  let x = 0;
+  let y = 0;
+  let delta_x = 0;
+  let delta_y = scroll_amount;
+  let actions = new test_driver.Actions()
+  .scroll(x, y, delta_x, delta_y, {origin: element});
+  return  actions.send();
+}
+
+function scrollElementLeft(element, scroll_amount) {
+  let x = 0;
+  let y = 0;
+  let delta_x = scroll_amount;
+  let delta_y = 0;
+  let actions = new test_driver.Actions()
+  .scroll(x, y, delta_x, delta_y, {origin: element});
+  return  actions.send();
+}
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-after-sequence-of-scrolls.tentative.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-after-sequence-of-scrolls.tentative.html
index 77bf029ced58c55..dab6dcc9bd8d67a 100644
--- a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-after-sequence-of-scrolls.tentative.html
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-after-sequence-of-scrolls.tentative.html
@@ -14,7 +14,7 @@
 }
 
 #innerDiv {
-  width: 500px;
+  width: 4000px;
   height: 4000px;
 }
 </style>
@@ -28,36 +28,64 @@
 
 <script>
 const target_div = document.getElementById('targetDiv');
-let scrollend_arrived = false;
-let scrollend_event_count = 0;
-
-function onScrollEnd(event) {
-  assert_false(event.cancelable);
-  assert_false(event.bubbles);
-  scrollend_arrived = true;
-  scrollend_event_count += 1;
+
+async function testWithMovePath(t, move_path) {
+  // Skip the test on a Mac as they do not support touch screens.
+  const isMac = navigator.platform.toUpperCase().indexOf('MAC')>=0;
+  if (isMac)
+    return;
+
+  await resetTargetScrollState(t, target_div);
+  await waitForCompositorReady();
+
+  verifyNoScrollendOnDocument(t);
+
+  let scrollend_count = 0;
+  const scrollend_listener = () => { scrollend_count += 1; };
+  target_div.addEventListener("scrollend", scrollend_listener);
+  t.add_cleanup(() => { target_div.removeEventListener('scrollend', scrollend_listener); });
+
+  const pointercancel_listener = () => {
+    assert_equals(scrollend_count, 0, 'scrollend should happen after pointercancel.');
+  };
+  target_div.addEventListener("pointercancel", pointercancel_listener);
+  t.add_cleanup(() => { target_div.removeEventListener('pointercancel', pointercancel_listener); });
+
+  // Because we have several pointer moves, we choose bigger timeout.
+  const timeoutMs = 3000;
+  const targetPointercancelPromise = waitForPointercancelEvent(t, target_div, timeoutMs);
+  const targetScrollendPromise = createScrollendPromiseForTarget(t, target_div, timeoutMs);
+
+  await touchScrollInTargetSequentiallyWithPause(target_div, move_path);
+
+  // Because we start scrolling after pointerdown, there is no pointerup, instead the target
+  // will receive a pointercancel, so we wait for pointercancel, and then continue.
+  await targetPointercancelPromise;
+  await targetScrollendPromise;
+  await verifyScrollStopped(t, target_div);
+  assert_equals(scrollend_count, 1, 'Only one scrollend event should be fired');
 }
 
 function runTest() {
   promise_test (async (t) => {
-    // Make sure that no scrollend event is sent to document.
-    document.addEventListener("scrollend",
-        t.unreached_func("document got unexpected scrollend event."));
-    await waitForCompositorCommit();
-
     // Scroll down & up & down on target div and wait for the target_div to get scrollend event.
-    target_div.addEventListener("scrollend", onScrollEnd);
     const move_path = [
-      { x: 0, y: -300}, // down
-      { x: 0, y: -100}, // up
-      { x: 0, y: -400}, // down
-      { x: 0, y: -200}, // up
+      { x: 0, y: -80 }, // Scroll down
+      { x: 0, y: -40 }, // Scroll up
+      { x: 0, y: -80 }, // Scroll down
     ];
-    await touchScrollInTargetSequentiallyWithPause(target_div, move_path, 150);
-
-    await waitFor(() => {return scrollend_arrived;},
-        'target_div did not receive scrollend event after sequence of scrolls on target.');
-    assert_equals(scrollend_event_count, 1);
+    await testWithMovePath(t, move_path);
   }, "Move down, up and down again, receive scrollend event only once");
+
+  promise_test (async (t) => {
+    // Scroll right & left & right on target div and wait for the target_div to get scrollend event.
+    const move_path = [
+      { x: -80, y: 0 }, // Scroll right
+      { x: -40, y: 0 }, // Scroll left
+      { x: -80, y: 0 }, // Scroll right
+    ];
+    await testWithMovePath(t, move_path);
+  }, "Move right, left and right again, receive scrollend event only once");
+
 }
 </script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-mandatory-snap-point-after-load.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-mandatory-snap-point-after-load.html
new file mode 100644
index 000000000000000..f3791134204497d
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-mandatory-snap-point-after-load.html
@@ -0,0 +1,87 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width">
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="scroll_support.js"></script>
+  <title>scrollend + mandatory scroll snap test</title>
+
+  <style>
+    #root {
+      width: 400px;
+      height: 400px;
+      overflow: auto;
+      scroll-snap-type: y mandatory;
+      border: 1px solid black;
+      --page-height: 400px;
+    }
+
+    #scroller {
+      height: 200px;
+      width: 200px;
+      overflow: auto;
+      border: 1px solid black;
+      --page-height: 200px;
+    }
+
+    .page {
+      height: var(--page-height);
+      scroll-snap-align: start;
+    }
+
+    .hidden {
+      display: none;
+    }
+  </style>
+</head>
+
+<body onload="runTests()">
+<div id="root" class="hidden">
+  <h1>scrollend + mandatory scroll snap test</h1>
+  <div id="scroller">
+    <div class="page">
+      <p>Page 1</p>
+    </div>
+    <div class="page">
+      <p>Page 2</p>
+    </div>
+    <div class="page">
+      <p>Page 3</p>
+    </div>
+  </div>
+
+  <div class="page">
+    <p>Page A</p>
+  </div>
+  <div class="page">
+    <p>Page B</p>
+  </div>
+  <div class="page">
+    <p>Page C</p>
+  </div>
+</div>
+
+<script>
+  function runTests() {
+    const root_div = document.getElementById("root");
+
+    promise_test(async (t) => {
+      const targetScrollendPromise = createScrollendPromiseForTarget(t, root_div);
+
+      await waitForNextFrame();
+      root_div.classList.remove("hidden");
+      await waitForNextFrame();
+
+      await targetScrollendPromise;
+      await verifyScrollStopped(t, root_div);
+    }, "scrollend event fired after load for mandatory snap point");
+  }
+</script>
+</body>
+
+</html>
\ No newline at end of file
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-programmatic-scroll.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-programmatic-scroll.html
index c6569e0bebbd9f8..449aea053512442 100644
--- a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-programmatic-scroll.html
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-programmatic-scroll.html
@@ -1,11 +1,19 @@
 <!DOCTYPE HTML>
-<meta name="timeout" content="long">
 <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="/resources/testdriver.js"></script>
 <script src="/resources/testdriver-actions.js"></script>
 <script src="/resources/testdriver-vendor.js"></script>
+<script src="/common/subset-tests-by-key.js"></script>
+<meta name="variant" content="?include=subframe-scrollTo-auto"/>
+<meta name="variant" content="?include=subframe-scrollTo-smooth"/>
+<meta name="variant" content="?include=subframe-scrollBy-auto"/>
+<meta name="variant" content="?include=subframe-scrollBy-smooth"/>
+<meta name="variant" content="?include=root-scrollTo-auto"/>
+<meta name="variant" content="?include=root-scrollTo-smooth"/>
+<meta name="variant" content="?include=root-scrollBy-auto"/>
+<meta name="variant" content="?include=root-scrollBy-smooth"/>
 <script src="scroll_support.js"></script>
 <style>
 html {
@@ -31,8 +39,8 @@
 </div>
 </body>
 <script>
-var element_scrollend_arrived = false;
-var document_scrollend_arrived = false;
+let element_scrollend_arrived = false;
+let document_scrollend_arrived = false;
 
 function onElementScrollEnd(event) {
   assert_false(event.cancelable);
@@ -47,89 +55,95 @@
   document_scrollend_arrived = true;
 }
 
-function callScrollFunction([scrollTarget, scrollFunction, args]) {
-  scrollTarget[scrollFunction](args);
-}
+let scroll_fn_variants = [
+  {
+    key: "subframe-scrollTo-auto",
+    target: targetDiv,
+    fn: "scrollTo",
+    behavior: "auto",
+    title: "Tests scrollend event for calling scrollTo with behavior 'auto' on subframe."
+  },
+  {
+    key: "subframe-scrollTo-smooth",
+    target: targetDiv,
+    fn: "scrollTo",
+    behavior: "smooth",
+    title: "Tests scrollend event for calling scrollTo with behavior 'smooth' on subframe."
+  },
+  {
+    key: "subframe-scrollBy-auto",
+    target: targetDiv,
+    fn: "scrollBy",
+    behavior: "auto",
+    title: "Tests scrollend event for calling scrollBy with behavior 'auto' on subframe."
+  },
+  {
+    key: "subframe-scrollBy-smooth",
+    target: targetDiv,
+    fn: "scrollBy",
+    behavior: "smooth",
+    title: "Tests scrollend event for calling scrollBy with behavior 'smooth' on subframe."
+  },
+  {
+    key: "root-scrollTo-auto",
+    target: document.scrollingElement,
+    fn: "scrollTo",
+    behavior: "auto",
+    title: "Tests scrollend event for calling scrollTo with behavior 'auto' on root."
+  },
+  {
+    key: "root-scrollTo-smooth",
+    target: document.scrollingElement,
+    fn: "scrollTo",
+    behavior: "smooth",
+    title: "Tests scrollend event for calling scrollTo with behavior 'smooth' on root."
+  },
+  {
+    key: "root-scrollBy-auto",
+    target: document.scrollingElement,
+    fn: "scrollBy",
+    behavior: "auto",
+    title: "Tests scrollend event for calling scrollBy with behavior 'auto' on root."
+  },
+  {
+    key: "root-scrollBy-smooth",
+    target: document.scrollingElement,
+    fn: "scrollBy",
+    behavior: "smooth",
+    title: "Tests scrollend event for calling scrollBy with behavior 'smooth' on root."
+  },
+];
 
 function runTest() {
-  let root_element = document.scrollingElement;
-  let target_div = document.getElementById("targetDiv");
 
-  promise_test (async (t) => {
+  async function testScrollFn(testInfo, t) {
     await waitForCompositorCommit();
-    target_div.addEventListener("scrollend", onElementScrollEnd);
-    document.addEventListener("scrollend", onDocumentScrollEnd);
 
-    let test_cases = [
-      [target_div, 200, 200, [target_div, "scrollTo", { top: 200, left: 200, behavior: "auto" }]],
-      [target_div, 0, 0, [target_div, "scrollTo", { top: 0, left: 0, behavior: "smooth" }]],
-      [root_element, 200, 200, [root_element, "scrollTo", { top: 200, left: 200, behavior: "auto" }]],
-      [root_element, 0, 0, [root_element, "scrollTo", { top: 0, left: 0, behavior: "smooth" }]],
-      [target_div, 200, 200, [target_div, "scrollBy", { top: 200, left: 200, behavior: "auto" }]],
-      [target_div, 0, 0, [target_div, "scrollBy", { top: -200, left: -200, behavior: "smooth" }]],
-      [root_element, 200, 200, [root_element, "scrollBy", { top: 200, left: 200, behavior: "auto" }]],
-      [root_element, 0, 0, [root_element, "scrollBy", { top: -200, left: -200, behavior: "smooth" }]]
-    ];
-
-    for(i = 0; i < test_cases.length; i++) {
-      let t = test_cases[i];
-      let target = t[0];
-      let expected_x = t[1];
-      let expected_y = t[2];
-      let scroll_datas = t[3];
+    targetDiv.addEventListener("scrollend", onElementScrollEnd);
+    document.addEventListener("scrollend", onDocumentScrollEnd);
 
-      callScrollFunction(scroll_datas);
-      await waitFor(() => { return element_scrollend_arrived || document_scrollend_arrived; }, target.tagName + "." + scroll_datas[1] + " did not receive scrollend event.");
-      if (target == root_element)
-        assert_false(element_scrollend_arrived);
-      else
-        assert_false(document_scrollend_arrived);
-      assert_equals(target.scrollLeft, expected_x, target.tagName + "." + scroll_datas[1] + " scrollLeft");
-      assert_equals(target.scrollTop, expected_y, target.tagName + "." + scroll_datas[1] + " scrollTop");
+    testInfo.target[testInfo.fn]({ top: 200, left: 200,
+                                   behavior: testInfo.behavior });
 
-      element_scrollend_arrived = false;
-      document_scrollend_arrived = false;
+    await waitFor(() => {
+      return element_scrollend_arrived || document_scrollend_arrived;
+    }, testInfo.target.tagName + "." + testInfo.fn + " did not receive scrollend event.");
+    if (testInfo.target == document.scrollingElement) {
+      assert_false(element_scrollend_arrived);
+    } else {
+      assert_false(document_scrollend_arrived);
     }
-  }, "Tests scrollend event for calling scroll functions.");
 
-  promise_test(async (t) => {
-    await waitForCompositorCommit();
-
-    let test_cases = [
-      [target_div, "scrollTop"],
-      [target_div, "scrollLeft"],
-      [root_element, "scrollTop"],
-      [root_element, "scrollLeft"]
-    ];
-    for (i = 0; i < test_cases.length; i++) {
-      let t = test_cases[i];
-      let target = t[0];
-      let attribute = t[1];
-      let position = 200;
+    assert_equals(testInfo.target.scrollLeft, 200,
+                  testInfo.target.tagName + "." + testInfo.fn + " scrollLeft");
+    assert_equals(testInfo.target.scrollTop, 200,
+                  testInfo.target.tagName + "." + testInfo.fn + " scrollTop");
+  }
 
-      target.style.scrollBehavior = "smooth";
-      target[attribute] = position;
-      await waitFor(() => { return element_scrollend_arrived || document_scrollend_arrived; }, target.tagName + "." + attribute + " did not receive scrollend event.");
-      if (target == root_element)
-        assert_false(element_scrollend_arrived);
-      else
-        assert_false(document_scrollend_arrived);
-      assert_equals(target[attribute], position, target.tagName + "." + attribute + " ");
-      element_scrollend_arrived = false;
-      document_scrollend_arrived = false;
+  scroll_fn_variants.forEach((testInfo) => {
+    subsetTestByKey(testInfo.key, promise_test,
+                    async (t) => testScrollFn(testInfo, t), testInfo.title);
+  });
 
-      await waitForCompositorCommit();
-      target.style.scrollBehavior = "auto";
-      target[attribute] = 0;
-      await waitFor(() => { return element_scrollend_arrived || document_scrollend_arrived; }, target.tagName + "." + attribute + " did not receive scrollend event.");
-      if (target == root_element)
-        assert_false(element_scrollend_arrived);
-      else
-        assert_false(document_scrollend_arrived);
-      assert_equals(target[attribute], 0, target.tagName + "." + attribute + " ");
-      element_scrollend_arrived = false;
-      document_scrollend_arrived = false;
-    }
-  }, "Tests scrollend event for changing scroll attributes.");
 }
 </script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-scroll-attr-change.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-scroll-attr-change.html
new file mode 100644
index 000000000000000..c96db1c749e9da8
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-scroll-attr-change.html
@@ -0,0 +1,147 @@
+<!DOCTYPE HTML>
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/common/subset-tests-by-key.js"></script>
+<meta name="variant" content="?include=subframe-scrollTop-smooth"/>
+<meta name="variant" content="?include=subframe-scrollLeft-smooth"/>
+<meta name="variant" content="?include=root-scrollTop-smooth"/>
+<meta name="variant" content="?include=root-scrollLeft-smooth"/>
+<meta name="variant" content="?include=subframe-scrollTop-auto"/>
+<meta name="variant" content="?include=subframe-scrollLeft-auto"/>
+<meta name="variant" content="?include=root-scrollTop-auto"/>
+<meta name="variant" content="?include=root-scrollLeft-auto"/>
+<script src="scroll_support.js"></script>
+<style>
+html {
+  height: 3000px;
+  width: 3000px;
+}
+#targetDiv {
+  width: 200px;
+  height: 200px;
+  overflow: scroll;
+}
+
+#innerDiv {
+  width: 400px;
+  height: 400px;
+}
+</style>
+
+<body style="margin:0" onload=runTest()>
+<div id="targetDiv">
+  <div id="innerDiv">
+  </div>
+</div>
+</body>
+<script>
+var element_scrollend_arrived = false;
+var document_scrollend_arrived = false;
+
+function onElementScrollEnd(event) {
+  assert_false(event.cancelable);
+  assert_false(event.bubbles);
+  element_scrollend_arrived = true;
+}
+
+function onDocumentScrollEnd(event) {
+  assert_false(event.cancelable);
+  // scrollend events are bubbled when the target node is document.
+  assert_true(event.bubbles);
+  document_scrollend_arrived = true;
+}
+
+let scroll_attr_change_variants = [
+  {
+    key: "subframe-scrollTop-smooth",
+    target: targetDiv,
+    behavior: "smooth",
+    attribute: "scrollTop",
+    title: "Tests scrollend event for [scrollTop] behavior:'smooth' on subframe."
+  },
+  {
+    key: "subframe-scrollLeft-smooth",
+    target: targetDiv,
+    behavior: "smooth",
+    attribute: "scrollLeft",
+    title: "Tests scrollend event for [scrollLeft] behavior:'smooth' on subframe."
+  },
+  {
+    key: "root-scrollTop-smooth",
+    target: document.scrollingElement,
+    behavior: "smooth",
+    attribute: "scrollTop",
+    title: "Tests scrollend event for [scrollTop] behavior:'smooth' on root."
+  },
+  {
+    key: "root-scrollLeft-smooth",
+    target: document.scrollingElement,
+    behavior: "smooth",
+    attribute: "scrollLeft",
+    title: "Tests scrollend event for [scrollLeft] behavior:'smooth' on root."
+  },
+  {
+    key: "subframe-scrollTop-auto",
+    target: targetDiv,
+    behavior: "auto",
+    attribute: "scrollTop",
+    title: "Tests scrollend event for [scrollTop] behavior:'auto' on subframe."
+  },
+  {
+    key: "subframe-scrollLeft-auto",
+    target: targetDiv,
+    behavior: "auto",
+    attribute: "scrollLeft",
+    title: "Tests scrollend event for [scrollLeft] behavior:'auto' on subframe."
+  },
+  {
+    key: "root-scrollTop-auto",
+    target: document.scrollingElement,
+    behavior: "auto",
+    attribute: "scrollTop",
+    title: "Tests scrollend event for [scrollTop] behavior:'auto' on root."
+  },
+  {
+    key: "root-scrollLeft-auto",
+    target: document.scrollingElement,
+    behavior: "auto",
+    attribute: "scrollLeft",
+    title: "Tests scrollend event for [scrollLeft] behavior:'auto' on root."
+  },
+];
+
+function runTest() {
+
+  async function testScrollAttrChange(testInfo, t) {
+    targetDiv.addEventListener("scrollend", onElementScrollEnd);
+    document.addEventListener("scrollend", onDocumentScrollEnd);
+
+    testInfo.target.style.scrollBehavior = testInfo.behavior;
+
+    await waitForCompositorCommit();
+
+    testInfo.target[testInfo.attribute] = 200;
+
+    await waitFor(() => {
+      return element_scrollend_arrived || document_scrollend_arrived;
+    }, testInfo.target.tagName + "." + testInfo.attribute + " did not receive scrollend event.");
+
+    if (testInfo.target == document.scrollingElement) {
+      assert_false(element_scrollend_arrived);
+    } else {
+      assert_false(document_scrollend_arrived);
+    }
+    assert_equals(testInfo.target[testInfo.attribute], 200,
+                  testInfo.target.tagName + "." + testInfo.attribute + " " + testInfo.behavior);
+  }
+
+  scroll_attr_change_variants.forEach((testInfo) => {
+    subsetTestByKey(testInfo.key, promise_test,
+                    async (t) => testScrollAttrChange(testInfo, t), testInfo.title);
+  })
+}
+</script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-scrollIntoView.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-scrollIntoView.html
index 8782b1dfee62374..40aa77f4764b6c4 100644
--- a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-scrollIntoView.html
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-for-scrollIntoView.html
@@ -108,10 +108,12 @@
     document.body.appendChild(out_div);
     await waitForCompositorCommit();
 
-    element_scrollend_arrived = false;
-    document_scrollend_arrived = false;
     inner_div.scrollIntoView({ inline: "end", block: "end", behavior: "auto" });
-    await waitFor(() => { return element_scrollend_arrived || document_scrollend_arrived; }, "Nested scrollIntoView did not receive scrollend event.");
+    const scrollend_events = [
+      waitForScrollendEventNoTimeout(out_div),
+      waitForScrollendEventNoTimeout(target_div)
+    ];
+    await Promise.all(scrollend_events);
     assert_equals(root_element.scrollLeft, 0, "Nested scrollIntoView root_element scrollLeft");
     assert_equals(root_element.scrollTop, 0, "Nested scrollIntoView root_element scrollTop");
     assert_equals(out_div.scrollLeft, 100, "Nested scrollIntoView out_div scrollLeft");
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-document.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-document.html
index 309045538834356..797c2eb53da0e31 100644
--- a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-document.html
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-document.html
@@ -7,64 +7,100 @@
 <script src="/resources/testdriver-vendor.js"></script>
 <script src="scroll_support.js"></script>
 <style>
-#targetDiv {
-  width: 200px;
-  height: 200px;
-  overflow: scroll;
-}
-
-#innerDiv {
-  width: 400px;
-  height: 400px;
-}
+  #hspacer {
+    height: 100px;
+    width: 100vw;
+    top: 0;
+    left: 200px;
+    /* on the right edge od targetDiv */
+    position: absolute;
+  }
+
+  #vspacer {
+    height: 100vh;
+    width: 100px;
+    position: absolute;
+  }
+
+  #targetDiv {
+    width: 200px;
+    height: 200px;
+    overflow: scroll;
+  }
+
+  #innerDiv {
+    width: 400px;
+    height: 400px;
+  }
 </style>
 
 <body style="margin:0" onload=runTest()>
-<div id="targetDiv">
-  <div id="innerDiv">
+  <div id="targetDiv">
+    <div id="innerDiv"></div>
   </div>
-</div>
+  <div id="hspacer"></div>
+  <div id="vspacer"></div>
 </body>
 
 <script>
-var target_div = document.getElementById('targetDiv');
-var horizontal_scrollend_arrived = false;
-var vertical_scrollend_arrived = false;
-function onHorizontalScrollEnd(event) {
-  assert_false(event.cancelable);
-  // scrollend events are bubbled when the target node is document.
-  assert_true(event.bubbles);
-  horizontal_scrollend_arrived = true;
-}
-function onVerticalScrollEnd(event) {
-  assert_false(event.cancelable);
-  // scrollend events are bubbled when the target node is document.
-  assert_true(event.bubbles);
-  vertical_scrollend_arrived = true;
-}
-
-function runTest() {
-  promise_test (async (t) => {
-    // Make sure that no scrollend event is sent to target_div.
-    target_div.addEventListener("scrollend",
-        t.unreached_func("target_div got unexpected scrollend event."));
-    await waitForCompositorCommit();
-
-    // Scroll left on target div and wait for the doc to get scrollend event.
-    document.addEventListener("scrollend", onHorizontalScrollEnd);
-    await touchScrollInTarget(300, target_div, 'left');
-    await waitFor(() => { return horizontal_scrollend_arrived; },
-        'Document did not receive scrollend event after scroll left on target.');
-    assert_equals(target_div.scrollLeft, 0);
-    document.removeEventListener("scrollend", onHorizontalScrollEnd);
-
-    // Scroll up on target div and wait for the doc to get scrollend event.
-    document.addEventListener("scrollend", onVerticalScrollEnd);
-    await touchScrollInTarget(300, target_div, 'up');
-    await waitFor(() => { return vertical_scrollend_arrived; },
-        'Document did not receive scrollend event after scroll up on target.');
-    assert_equals(target_div.scrollTop, 0);
-  }, 'Tests that the document gets scrollend event when no element scrolls by ' +
-     'touch.');
-}
+  var target_div = document.getElementById('targetDiv');
+  async function resetScrollers(test) {
+    await waitForScrollReset(test, target_div);
+    await waitForScrollReset(test, document.scrollingElement);
+  }
+
+  function fail() {
+    assert_true(false);
+  }
+
+  function runTest() {
+    promise_test(async (t) => {
+      await resetScrollers(t);
+      await waitForCompositorCommit();
+
+      assert_equals(document.scrollingElement.scrollTop, 0,
+        "document should not be scrolled");
+
+      let scrollend_promise = waitForScrollendEvent(t, target_div);
+      let max_target_div_scroll_top = target_div.scrollHeight - target_div.clientHeight;
+      target_div.scrollTo({ top: target_div.scrollHeight, left: 0 });
+      await scrollend_promise;
+      assert_approx_equals(target_div.scrollTop, max_target_div_scroll_top, 1,
+        "target_div should be fully scrolled down");
+
+      scrollend_promise = waitForScrollendEvent(t, document, 2000);
+      target_div.addEventListener("scrollend", fail);
+      // Scroll up on target div and wait for the doc to get scrollend event.
+      await scrollElementDown(target_div, target_div.clientHeight + 25);
+      await scrollend_promise;
+
+      target_div.removeEventListener("scrollend", fail);
+      assert_greater_than(document.scrollingElement.scrollTop, target_div.clientHeight - 1,
+        "document is scrolled by the height of target_div");
+    }, "testing, vertical");
+
+    promise_test(async (t) => {
+      await resetScrollers(t);
+      await waitForCompositorCommit();
+
+      assert_equals(document.scrollingElement.scrollLeft, 0,
+        "document should not be scrolled");
+
+      let scrollend_promise = waitForScrollendEvent(t, target_div);
+      let max_target_div_scroll_left = target_div.scrollWidth - target_div.clientWidth;
+      target_div.scrollTo({ left: target_div.scrollWidth, top: 0 });
+      await scrollend_promise;
+      assert_approx_equals(target_div.scrollLeft, max_target_div_scroll_left, 1,
+        "target_div should be fully scrolled right");
+
+      scrollend_promise = waitForScrollendEvent(t, document, 2000);
+      target_div.addEventListener("scrollend", fail);
+      await scrollElementLeft(target_div, target_div.clientWidth + 25);
+      await scrollend_promise;
+
+      target_div.removeEventListener("scrollend", fail);
+      assert_greater_than(document.scrollingElement.scrollLeft, target_div.clientWidth - 1,
+        "document is scrolled by the height of target_div");
+    }, "testing, horizontal");
+  }
 </script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-element-with-overscroll-behavior.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-element-with-overscroll-behavior.html
index acad168e56c995d..edda88e7cb20647 100644
--- a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-element-with-overscroll-behavior.html
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-element-with-overscroll-behavior.html
@@ -7,96 +7,167 @@
 <script src="/resources/testdriver-vendor.js"></script>
 <script src="scroll_support.js"></script>
 <style>
-#overscrollXDiv {
-  width: 600px;
-  height: 600px;
-  overflow: scroll;
-  overscroll-behavior-x: contain;
-}
-#overscrollYDiv {
-  width: 500px;
-  height: 500px;
-  overflow: scroll;
-  overscroll-behavior-y: none;
-}
-#targetDiv {
-  width: 400px;
-  height: 400px;
-  overflow: scroll;
-}
-.content {
-  width:800px;
-  height:800px;
-}
+  #overscrollXDiv {
+    width: 200px;
+    height: 200px;
+    overflow: scroll;
+    overscroll-behavior-x: contain;
+    border: solid 1px black;
+    display: grid;
+    /* Places content and targetXDiv beside each other. */
+    grid-template-columns: 500px 100px;
+  }
+
+  #overscrollYDiv {
+    width: 200px;
+    height: 200px;
+    overflow: scroll;
+    overscroll-behavior-y: none;
+    border: solid 1px black;
+  }
+
+  #targetXDiv {
+    width: 100px;
+    height: 100px;
+    overflow: scroll;
+    border: solid 1px black;
+  }
+
+  #targetYDiv {
+    width: 100px;
+    height: 100px;
+    overflow: scroll;
+    border: solid 1px black;
+  }
+
+  .content {
+    width: 500px;
+    height: 500px;
+  }
+
+  #spacer {
+    height: 200vh;
+    width: 200vw;
+    border: solid 1px black;
+  }
 </style>
 
 <body style="margin:0" onload=runTest()>
-<div id="overscrollXDiv">
-  <div class=content>
-    <div id="overscrollYDiv">
-      <div class=content>
-        <div id="targetDiv">
-          <div class="content">
-          </div>
-        </div>
+  <div id="overscrollXDiv">
+    <div class="content"></div>
+    <div id="targetXDiv">
+      <div class="content">
       </div>
     </div>
   </div>
-</div>
+  <div id="overscrollYDiv">
+    <div class="content"></div>
+    <!-- Place targetYDiv below content so that is in view when
+         overscrollYDiv is scrolled all the way down -->
+    <div id="targetYDiv">
+      <div class="content">
+      </div>
+    </div>
+  </div>
+  <div id="spacer"></div>
 </body>
 
 <script>
-var target_div = document.getElementById('targetDiv');
-var horizontal_scrollend_arrived = false;
-var vertical_scrollend_arrived = false;
-function onHorizontalScrollEnd(event) {
-  assert_false(event.cancelable);
-  assert_false(event.bubbles);
-  horizontal_scrollend_arrived = true;
-}
-function onVerticalScrollEnd(event) {
-  assert_false(event.cancelable);
-  assert_false(event.bubbles);
-  vertical_scrollend_arrived = true;
-}
-// Test that both "onscrollend" and addEventListener("scrollend"... work.
-document.getElementById('overscrollXDiv').onscrollend = onHorizontalScrollEnd;
-document.getElementById('overscrollYDiv').
+  var horizontal_scrollend_arrived = false;
+  var vertical_scrollend_arrived = false;
+  let scrollers = [document.scrollingElement, targetXDiv, targetYDiv,
+                   overscrollXDiv, overscrollYDiv];
+
+  async function resetScrollers(test) {
+    for (const scroller of scrollers) {
+      await resetTargetScrollState(test, scroller);
+    }
+  }
+  function onHorizontalScrollEnd(event) {
+    assert_false(event.cancelable);
+    assert_false(event.bubbles);
+    horizontal_scrollend_arrived = true;
+  }
+  function onVerticalScrollEnd(event) {
+    assert_false(event.cancelable);
+    assert_false(event.bubbles);
+    vertical_scrollend_arrived = true;
+  }
+  // Test that both "onscrollend" and addEventListener("scrollend"... work.
+  document.getElementById('overscrollXDiv').onscrollend = onHorizontalScrollEnd;
+  document.getElementById('overscrollYDiv').
     addEventListener("scrollend", onVerticalScrollEnd);
 
-function runTest() {
-  promise_test (async (t) => {
-    // Make sure that no scrollend event is sent to document or target_div.
-    document.addEventListener("scrollend",
-        t.unreached_func("Document got unexpected scrollend event."));
-    target_div.addEventListener("scrollend",
-        t.unreached_func("target_div got unexpected scrollend event."));
-    await waitForCompositorCommit();
-
-    // Scroll left on target div and wait for the element with overscroll-x to
-    // get scrollend event.
-    await touchScrollInTarget(300, target_div, 'left');
-    await waitFor(() => { return horizontal_scrollend_arrived; },
-        'Expected element did not receive scrollend event after scroll left ' +
-        'on target.');
-    assert_equals(target_div.scrollLeft, 0);
-
-    let touchEndPromise = new Promise((resolve) => {
-      target_div.addEventListener("touchend", resolve);
-    });
-    await touchScrollInTarget(300, target_div, 'up');
-
-    // The scrollend event should never be fired before the gesture has completed.
-    await touchEndPromise;
-
-    // Ensure we wait at least a tick after the touch end.
-    await waitForCompositorCommit();
-
-    // We should not trigger a scrollend event for a scroll that did not change
-    // the scroll position.
-    assert_equals(vertical_scrollend_arrived, false);
-    assert_equals(target_div.scrollTop, 0);
-  }, 'Tests that the last element in the cut scroll chain gets scrollend ' +
-     'event when no element scrolls by touch.');
-}
+  function runTest() {
+    promise_test(async (t) => {
+      await resetScrollers(t);
+      await waitForCompositorCommit();
+
+      // Make sure that no scrollend event is sent to document.
+      document.addEventListener("scrollend",
+      t.unreached_func("Document got unexpected scrollend event."));
+      let scrollend_promise;
+
+      scrollend_promise = waitForScrollendEvent(t, targetXDiv, 2000);
+      targetXDiv.scrollLeft = targetXDiv.scrollWidth;
+      await scrollend_promise;
+
+      scrollend_promise = waitForScrollendEvent(t, overscrollXDiv, 2000);
+      overscrollXDiv.scrollLeft = overscrollXDiv.scrollWidth;
+      await scrollend_promise;
+      horizontal_scrollend_arrived = false;
+
+      assert_equals(targetXDiv.scrollLeft,
+                    targetXDiv.scrollWidth - targetXDiv.clientWidth);
+      assert_equals(overscrollXDiv.scrollLeft,
+                    overscrollXDiv.scrollWidth - overscrollXDiv.clientWidth);
+      // Attempt to scroll targetXDiv further to the right.
+      // targetXDiv and overscrollXDiv are already fully scrolled right but the
+      // scroll should not propagate to the document because of
+      // overscroll-behavior-x: contain on overscrollXDiv.
+      let touchEndPromise = new Promise((resolve) => {
+        targetXDiv.addEventListener("touchend", resolve);
+      });
+      await touchScrollInTarget(100, targetXDiv, 'right');
+      // The scrollend event should never be fired before the gesture has
+      // completed.
+      await touchEndPromise;
+
+      scrollend_promise = waitForScrollendEvent(t, targetYDiv, 2000);
+      targetYDiv.scrollTop = targetXDiv.scrollHeight;
+      await scrollend_promise;
+
+      scrollend_promise = waitForScrollendEvent(t, overscrollYDiv, 2000);
+      overscrollYDiv.scrollTop = overscrollYDiv.scrollHeight;
+      await scrollend_promise;
+      vertical_scrollend_arrived = false;
+
+      assert_equals(targetYDiv.scrollTop,
+                    targetYDiv.scrollHeight - targetYDiv.clientHeight);
+      assert_equals(overscrollYDiv.scrollTop,
+                    overscrollYDiv.scrollHeight - overscrollYDiv.clientHeight);
+      // Attempt to scroll targetYDiv further down.
+      // targetYDiv and overscrollYDiv are already fully scrolled down but the
+      // scroll should not propagate to the document because of
+      // overscroll-behavior-y: none on overscrollYDiv.
+      touchEndPromise = new Promise((resolve) => {
+        targetYDiv.addEventListener("touchend", resolve);
+      });
+      await touchScrollInTarget(50, targetYDiv, 'down');
+      // The scrollend event should never be fired before the gesture has
+      // completed.
+      await touchEndPromise;
+
+      // Ensure we wait at least a tick after the touch end.
+      await waitForCompositorCommit();
+
+      // We should not trigger a scrollend event for a scroll that did not
+      // change the scroll position.
+      assert_equals(horizontal_scrollend_arrived, false,
+                    "overscrollXDiv should not receive scrollend");
+      assert_equals(vertical_scrollend_arrived, false,
+                    "overscrollYDiv should not receive scrollend");
+    }, "Tests that the scroll is not propagated beyond div with non-auto " +
+       "overscroll-behavior.");
+  }
 </script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-scrolled-element.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-scrolled-element.html
deleted file mode 100644
index 734339694220ccc..000000000000000
--- a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-scrolled-element.html
+++ /dev/null
@@ -1,68 +0,0 @@
-<!DOCTYPE HTML>
-<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script src="/resources/testdriver.js"></script>
-<script src="/resources/testdriver-actions.js"></script>
-<script src="/resources/testdriver-vendor.js"></script>
-<script src="scroll_support.js"></script>
-<style>
-#scrollableDiv {
-  width: 200px;
-  height: 200px;
-  overflow: scroll;
-}
-
-#innerDiv {
-  width: 400px;
-  height: 400px;
-}
-</style>
-
-<body style="margin:0" onload=runTest()>
-<div id="scrollableDiv">
-  <div id="innerDiv">
-  </div>
-</div>
-</body>
-
-<script>
-var scrolling_div = document.getElementById('scrollableDiv');
-var horizontal_scrollend_arrived = false;
-var vertical_scrollend_arrived = false;
-function onHorizontalScrollEnd(event) {
-  assert_false(event.cancelable);
-  assert_false(event.bubbles);
-  horizontal_scrollend_arrived = true;
-}
-function onVerticalScrollEnd(event) {
-  assert_false(event.cancelable);
-  assert_false(event.bubbles);
-  vertical_scrollend_arrived = true;
-}
-scrolling_div.addEventListener("scrollend", onHorizontalScrollEnd);
-scrolling_div.addEventListener("scrollend", onVerticalScrollEnd);
-
-function runTest() {
-  promise_test (async (t) => {
-    // Make sure that no scrollend event is sent to document.
-    document.addEventListener("scrollend",
-        t.unreached_func("Document got unexpected scrollend event."));
-    await waitForCompositorCommit();
-
-    // Do a horizontal scroll and wait for scrollend event.
-    await touchScrollInTarget(300, scrolling_div, 'right');
-    await waitFor(() => { return horizontal_scrollend_arrived; },
-        'Scroller did not receive scrollend event after horizontal scroll.');
-    assert_equals(scrolling_div.scrollWidth - scrolling_div.scrollLeft,
-                scrolling_div.clientWidth);
-
-    // Do a vertical scroll and wait for scrollend event.
-    await touchScrollInTarget(300, scrolling_div, 'down');
-    await waitFor(() => { return vertical_scrollend_arrived; },
-        'Scroller did not receive scrollend event after vertical scroll.');
-    assert_equals(scrolling_div.scrollHeight - scrolling_div.scrollTop,
-                scrolling_div.clientHeight);
-  }, 'Tests that the scrolled element gets scrollend event at the end of touch scrolling.');
-}
-</script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-window.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-window.html
index ef72f56d2ba9d62..d2fd6f4d3158a5e 100644
--- a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-window.html
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fired-to-window.html
@@ -7,49 +7,63 @@
 <script src="/resources/testdriver-vendor.js"></script>
 <script src="scroll_support.js"></script>
 <style>
-#targetDiv {
-  width: 200px;
-  height: 200px;
-  overflow: scroll;
-}
-
-#innerDiv {
-  width: 400px;
-  height: 400px;
-}
+  #spacer {
+    height: 100vh;
+    width: 100px;
+  }
+  #targetDiv {
+    width: 200px;
+    height: 200px;
+    overflow: scroll;
+  }
+  #innerDiv {
+    width: 400px;
+    height: 400px;
+  }
 </style>
 
 <body style="margin:0" onload=runTest()>
-<div id="targetDiv">
-  <div id="innerDiv">
+  <div id="targetDiv">
+    <div id="innerDiv"></div>
   </div>
-</div>
+  <div id="spacer"></div>
 </body>
 
 <script>
-var target_div = document.getElementById('targetDiv');
-var scrollend_arrived = false;
-function onScrollEnd(event) {
-  assert_false(event.cancelable);
-  // scrollend events targetting document are bubbled to the window.
-  assert_true(event.bubbles);
-  scrollend_arrived = true;
-}
-window.addEventListener("scrollend", onScrollEnd);
-
-function runTest() {
-  promise_test (async (t) => {
-    // Make sure that no scrollend event is sent to target_div.
-    target_div.addEventListener("scrollend",
-        t.unreached_func("target_div got unexpected scrollend event."));
-    await waitForCompositorCommit();
-
-    // Scroll up on target div and wait for the doc to get scrollend event.
-    await touchScrollInTarget(300, target_div, 'up');
-    await waitFor(() => { return scrollend_arrived; },
-        'Window did not receive scrollend event after scroll up on target.');
-    assert_equals(target_div.scrollTop, 0);
-  }, 'Tests that the window gets scrollend event when no element scrolls ' +
-     'after touch scrolling.');
-}
+  var target_div = document.getElementById('targetDiv');
+  async function resetScrollers(test) {
+    await waitForScrollReset(test, target_div);
+    await waitForScrollReset(test, document.scrollingElement);
+  }
+
+  function fail() {
+    assert_true(false);
+  }
+
+  function runTest() {
+    promise_test(async (t) => {
+      await resetScrollers(t);
+      await waitForCompositorCommit();
+
+      assert_equals(document.scrollingElement.scrollTop, 0,
+        "document should not be scrolled");
+
+      let scrollend_promise = waitForScrollendEventNoTimeout(target_div);
+      let max_target_div_scroll_top = target_div.scrollHeight - target_div.clientHeight;
+      target_div.scrollTo({ top: target_div.scrollHeight, left: 0 });
+      await scrollend_promise;
+      assert_approx_equals(target_div.scrollTop, max_target_div_scroll_top, 1,
+        "target_div should be fully scrolled down");
+
+      scrollend_promise = waitForScrollendEventNoTimeout(window);
+      target_div.addEventListener("scrollend", fail);
+      // Scroll up on target div and wait for the doc to get scrollend event.
+      await scrollElementDown(target_div, target_div.clientHeight + 25);
+      await scrollend_promise;
+
+      target_div.removeEventListener("scrollend", fail);
+      assert_greater_than(document.scrollingElement.scrollTop, target_div.clientHeight - 1,
+        "document is scrolled by the height of target_div");
+    }, "testing, vertical");
+  }
 </script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-on-visual-viewport.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-on-visual-viewport.html
new file mode 100644
index 000000000000000..99a281480ff11f3
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-on-visual-viewport.html
@@ -0,0 +1,68 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/visual-viewport/viewport_support.js"></script>
+<script src="/dom/events/scrolling/scroll_support.js"></script>
+</head>
+<body>
+<style>
+  .large {
+    height: 200vh;
+    width: 200vw;
+    border: solid 1px black;
+  }
+</style>
+<div class="large"></div>
+<script>
+  window.onload = async () => {
+    async function pan_viewport_test(add_event_listener_func) {
+      const preScrollVisualViewportOffsetTop = visualViewport.offsetTop;
+      const preScrollWindowScrollOffset = window.scrollY;
+
+      const scrollend_promise = add_event_listener_func();
+
+      const scrollAmount = 50;
+      await touchScrollInTarget(scrollAmount, document.documentElement, "up");
+      await scrollend_promise;
+
+      assert_less_than(visualViewport.offsetTop,
+        preScrollVisualViewportOffsetTop,
+        `visualViewport should be scrolled.`);
+      assert_equals(window.scrollY, preScrollWindowScrollOffset,
+        "the window should not scroll.");
+      // No need to undo scroll; subsequent test has room to scroll further.
+    }
+
+    await waitForCompositorCommit();
+    await pinchZoomIn();
+    assert_greater_than(visualViewport.scale, 1, "page should be zoomed in.");
+
+    promise_test(async (t) => {
+      await pan_viewport_test(() => {
+        return new Promise((resolve) => {
+          visualViewport.addEventListener("scrollend", resolve, { once: true});
+        });
+      });
+    }, "scrollend listener added via addEventlistener fires when the visual " +
+    "viewport is panned.");
+
+    promise_test(async (t) => {
+      await pan_viewport_test((t) => {
+        return new Promise((resolve) => {
+          visualViewport.onscrollend = () => {
+            visualViewport.onscrollend = undefined;
+            resolve();
+          }
+        });
+      });
+    }, "visualviewport.onscrollend fires when the visual viewport is panned.");
+  }
+</script>
+</body>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-to-iframe-inner-frame.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-to-iframe-inner-frame.html
new file mode 100644
index 000000000000000..115e583c067ebd3
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-to-iframe-inner-frame.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html>
+  <style>
+    body {
+      margin: 0px;
+    }
+    #spacer {
+      height: 120vh;
+      width: 120vw;
+      border: solid 1px black;
+    }
+    #scroller {
+      height: 200px;
+      width: 200px;
+      overflow: scroll;
+      border: solid 1px red;
+    }
+    #inner-spacer {
+      height: 400px;
+      width: 400px;
+      border: solid 1px black;
+    }
+  </style>
+  <body>
+    <div id="scroller" tabindex=0>
+      <div id="inner-spacer"></div>
+    </div>
+    <div id="spacer"></div>
+  </body>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-to-iframe-window.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-to-iframe-window.html
new file mode 100644
index 000000000000000..9cd3b421fe9036b
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-fires-to-iframe-window.html
@@ -0,0 +1,77 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+  <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="scroll_support.js"></script>
+  <script src="scrollend-user-scroll-common.js"></script>
+  <style>
+    iframe {
+      height: 300px;
+      width: 300px;
+    }
+  </style>
+</head>
+
+<body style="margin:0" onload=runTest()>
+  <iframe id="frame" src="scrollend-event-fires-to-iframe-inner-frame.html"></iframe>
+</body>
+
+<script>
+  function runTest() {
+    let target_div = frame.contentDocument.getElementById("scroller");
+    //Tests for scrollend events on an element within an iframe.
+    promise_test(async (t) => {
+      await test_scrollend_on_touch_drag(t, target_div);
+    }, 'Tests that the target_div within iframe gets scrollend event when touch ' +
+    'dragging.');
+
+    promise_test(async (t) => {
+      await test_scrollend_on_scrollbar_gutter_click(t, target_div);
+    }, 'Tests that the target_div within iframe gets scrollend event when ' +
+    'clicking scrollbar.');
+
+    // Same issue as previous test.
+    promise_test(async (t) => {
+      await test_scrollend_on_scrollbar_thumb_drag(t, target_div);
+    }, 'Tests that the target_div within iframe gets scrollend event when ' +
+    'dragging the scrollbar thumb.');
+
+    promise_test(async (t) => {
+      await test_scrollend_on_mousewheel_scroll(t, target_div, frame);
+    }, 'Tests that the target_div within iframe gets scrollend event when mouse ' +
+    'wheel scrolling.');
+
+    promise_test(async (t) => {
+      await test_scrollend_on_keyboard_scroll(t, target_div);
+    }, 'Tests that the target_div within iframe gets scrollend event when ' +
+    'sending DOWN key to the target.');
+
+    // Test for scrollend events on the iframe's window.
+    // TODO: add similar tests with different input modes.
+    promise_test(async (t) => {
+      let scroller = frame.contentDocument.scrollingElement;
+
+      await waitForScrollReset(t, scroller);
+      await waitForCompositorReady();
+
+      const targetScrollendPromise = waitForScrollendEventNoTimeout(frame.contentDocument);
+      verifyNoScrollendOnDocument(t);
+
+      let x = target_div.getBoundingClientRect().width + 20;
+      let y = 20;
+      let dy = 30;
+      await new test_driver.Actions().scroll(x, y, 0, dy).send();
+      await targetScrollendPromise;
+      assert_equals(scroller.scrollTop, dy, 'window scrolled by mousewheel');
+    }, 'scrollend fires to iframe window on mousewheelscroll');
+  }
+
+</script>
+
+</html>
\ No newline at end of file
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-for-user-scroll.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-for-user-scroll.html
index 5146c5f719a1e47..a06843a35e7ec9c 100644
--- a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-for-user-scroll.html
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-for-user-scroll.html
@@ -8,6 +8,7 @@
 <script src="/resources/testdriver-actions.js"></script>
 <script src="/resources/testdriver-vendor.js"></script>
 <script src="scroll_support.js"></script>
+<script src="scrollend-user-scroll-common.js"></script>
 <style>
     #targetDiv {
         width: 200px;
@@ -31,169 +32,33 @@
 <script>
 var target_div = document.getElementById('targetDiv');
 
-async function resetTargetScrollState(test) {
-  if (target_div.scrollTop != 0 || target_div.scrollLeft != 0) {
-    target_div.scrollTop = 0;
-    target_div.scrollLeft = 0;
-    return waitForScrollendEvent(test, target_div);
-  }
-}
-
-async function verifyScrollStopped(test) {
-  const unscaled_pause_time_in_ms = 100;
-  const x = target_div.scrollLeft;
-  const y = target_div.scrollTop;
-  return new Promise(resolve => {
-    test.step_timeout(() => {
-      assert_equals(x, target_div.scrollLeft);
-      assert_equals(y, target_div.scrollTop);
-      resolve();
-    }, unscaled_pause_time_in_ms);
-  });
-}
-
-async function verifyNoScrollendOnDocument(test) {
-  const callback =
-      test.unreached_func("window got unexpected scrollend event.");
-  window.addEventListener('scrollend', callback);
-}
-
-async function createScrollendPromise(test) {
-  return waitForScrollendEvent(test, target_div).then(evt => {
-      assert_false(evt.cancelable, 'Event is not cancelable');
-      assert_false(evt.bubbles, 'Event targeting element does not bubble');
-  });
-}
-
 function runTest() {
   promise_test(async (t) => {
-    // Skip the test on a Mac as they do not support touch screens.
-    const isMac = navigator.platform.toUpperCase().indexOf('MAC')>=0;
-    if (isMac)
-      return;
-
-    await resetTargetScrollState(t);
-    await waitForCompositorCommit();
-
-    const targetScrollendPromise = createScrollendPromise(t);
-    verifyNoScrollendOnDocument(t);
-
-    // Perform a touch drag on target div and wait for target_div to get
-    // a scrollend event.
-    await new test_driver.Actions()
-        .addPointer('TestPointer', 'touch')
-        .pointerMove(0, 0, {origin: target_div}) // 0, 0 is center of element.
-        .pointerDown()
-        .addTick()
-        .pointerMove(0, -40, {origin: target_div}) //  Drag up to move down.
-        .addTick()
-        .pause(200) //  Prevent inertial scroll.
-        .pointerUp()
-        .send();
-
-    await targetScrollendPromise;
-
-    assert_true(target_div.scrollTop > 0);
-    await verifyScrollStopped(t);
+    await test_scrollend_on_touch_drag(t, target_div);
   }, 'Tests that the target_div gets scrollend event when touch dragging.');
 
   promise_test(async (t) => {
-    // Skip test on platforms that do not have a visible scrollbar (e.g.
-    // overlay scrollbar).
-    const scrollbar_width = target_div.offsetWidth - target_div.clientWidth;
-    if (scrollbar_width == 0)
-      return;
-
-    await resetTargetScrollState(t);
-    await waitForCompositorCommit();
-
-    const targetScrollendPromise = createScrollendPromise(t);
-    verifyNoScrollendOnDocument(t);
-
-    const bounds = target_div.getBoundingClientRect();
-    const x = bounds.right - scrollbar_width / 2;
-    const y = bounds.bottom - 20;
-    await new test_driver.Actions()
-        .addPointer('TestPointer', 'mouse')
-        .pointerMove(x, y, {origin: 'viewport'})
-        .pointerDown()
-        .addTick()
-        .pointerUp()
-        .send();
-
-    await targetScrollendPromise;
-    assert_true(target_div.scrollTop > 0);
-    await verifyScrollStopped(t);
+    await test_scrollend_on_scrollbar_gutter_click(t, target_div);
   }, 'Tests that the target_div gets scrollend event when clicking ' +
      'scrollbar.');
 
   // Same issue as previous test.
   promise_test(async (t) => {
-    // Skip test on platforms that do not have a visible scrollbar (e.g.
-    // overlay scrollbar).
-    const scrollbar_width = target_div.offsetWidth - target_div.clientWidth;
-    if (scrollbar_width == 0)
-      return;
-
-    resetTargetScrollState(t);
-    const targetScrollendPromise = createScrollendPromise(t);
-    verifyNoScrollendOnDocument(t);
-
-    const bounds = target_div.getBoundingClientRect();
-    const x = bounds.right - scrollbar_width / 2;
-    const y = bounds.top + 30;
-    const dy = 30;
-    await new test_driver.Actions()
-        .addPointer('TestPointer', 'mouse')
-        .pointerMove(x, y, { origin: 'viewport' })
-        .pointerDown()
-        .pointerMove(x, y + dy, { origin: 'viewport' })
-        .addTick()
-        .pointerUp()
-        .send();
-
-    await targetScrollendPromise;
-    assert_true(target_div.scrollTop > 0);
-    await verifyScrollStopped(t);
+    await test_scrollend_on_scrollbar_thumb_drag(t, target_div);
   }, 'Tests that the target_div gets scrollend event when dragging the ' +
       'scrollbar thumb.');
 
   promise_test(async (t) => {
-    resetTargetScrollState(t);
-    const targetScrollendPromise = createScrollendPromise(t);
-    verifyNoScrollendOnDocument(t);
-
-    const x = 0;
-    const y = 0;
-    const dx = 0;
-    const dy = 40;
-    const duration_ms = 10;
-    await new test_driver.Actions()
-        .scroll(x, y, dx, dy, { origin: target_div }, duration_ms)
-        .send();
-
-    await targetScrollendPromise;
-    assert_true(target_div.scrollTop > 0);
-    await verifyScrollStopped(t);
+    await test_scrollend_on_mousewheel_scroll(t, target_div);
   }, 'Tests that the target_div gets scrollend event when mouse wheel ' +
      'scrolling.');
 
   promise_test(async (t) => {
-    await resetTargetScrollState(t);
-    await waitForCompositorCommit();
-
-    verifyNoScrollendOnDocument(t);
-    const targetScrollendPromise = createScrollendPromise(t);
-
-    target_div.focus();
-    window.test_driver.send_keys(target_div, '\ue015');
-
-    await targetScrollendPromise;
-    assert_true(target_div.scrollTop > 0);
-    await verifyScrollStopped(t);
+    await test_scrollend_on_keyboard_scroll(t, target_div);
   }, 'Tests that the target_div gets scrollend event when sending DOWN key ' +
      'to the target.');
 }
 
+
 </script>
 </html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-event-not-fired-on-no-scroll.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-not-fired-on-no-scroll.html
new file mode 100644
index 000000000000000..870e15546f54d26
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-event-not-fired-on-no-scroll.html
@@ -0,0 +1,114 @@
+<!DOCTYPE HTML>
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="scroll_support.js"></script>
+<style>
+  #spacer {
+    height: 100vh;
+    width: 100px;
+    position: relative;
+  }
+
+  #targetDiv {
+    width: 200px;
+    height: 200px;
+    overflow: scroll;
+  }
+
+  #innerDiv {
+    width: 400px;
+    height: 400px;
+  }
+</style>
+
+<body style="margin:0" onload=runTest()>
+  <div id="targetDiv">
+    <!-- This test uses button elements as a consistent mechanism for
+      ensuring that focus is on the correct scrolling element when
+      scrolling via keys -->
+    <button id="targetButton">target</button>
+    <div id="innerDiv"></div>
+  </div>
+  <button id="docButton">doc</button>
+  <div id="spacer"></div>
+</body>
+
+<script>
+  var target_div = document.getElementById('targetDiv');
+
+  async function resetScrollers(test) {
+    await waitForScrollReset(test, target_div);
+    await waitForScrollReset(test, document.scrollingElement);
+  }
+
+  function getBoundingClientRect(element) {
+    if (element == document) {
+      return document.documentElement.getBoundingClientRect();
+    }
+    return element.getBoundingClientRect();
+  }
+
+  async function upwardScroll(scrolling_element, button_element, scroll_type) {
+    if (scroll_type == "wheel") {
+      let x = 0;
+      let y = 0;
+      let delta_x = 0;
+      let delta_y = -50;
+      let actions = new test_driver.Actions()
+      .scroll(x, y, delta_x, delta_y, {origin: scrolling_element});
+      await actions.send();
+    } else if (scroll_type == "keys") {
+      const num_keydowns = 5;
+      const arrowUp = '\uE013';
+      for (let i = 0; i < num_keydowns; i++) {
+        await test_driver.send_keys(button_element, arrowUp);
+      }
+    }
+  }
+
+  async function testScrollendNotFiredOnNoScroll(test, scrolling_element,
+                                                 listening_element,
+                                                 button_element, scroll_type) {
+    await resetScrollers(test);
+    await waitForCompositorCommit();
+
+    assert_greater_than(scrolling_element.scrollHeight,
+                        scrolling_element.clientHeight);
+    assert_equals(scrolling_element.scrollTop, 0);
+
+    let scrollend_promise = waitForScrollendEvent(test, listening_element).then(
+      (/*resolve*/) => {
+        assert_true(false, "no scroll, so no scrollend expected");
+      },
+      (/*reject*/) => { /* Did not see scrollend, which is okay. */ }
+    );
+    await upwardScroll(scrolling_element, button_element, scroll_type);
+    await scrollend_promise;
+  }
+
+  function runTest() {
+    promise_test(async (t) => {
+      await testScrollendNotFiredOnNoScroll(t, target_div, target_div,
+                                            targetButton, "wheel");
+    }, "No scroll via wheel on div shouldn't fire scrollend.");
+
+    promise_test(async (t) => {
+      await testScrollendNotFiredOnNoScroll(t, target_div, target_div,
+                                            targetButton, "keys");
+    }, "No scroll via keys on div shouldn't fire scrollend.");
+
+    promise_test(async (t) => {
+      await testScrollendNotFiredOnNoScroll(t, document.scrollingElement,
+                                            document, docButton, "wheel");
+    }, "No scroll via wheel on document shouldn't fire scrollend.");
+
+    promise_test(async (t) => {
+      await testScrollendNotFiredOnNoScroll(t, document.scrollingElement,
+                                            document, docButton, "keys");
+    }, "No scroll via keys on document shouldn't fire scrollend.")
+  }
+</script>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-fires-to-text-input.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-fires-to-text-input.html
new file mode 100644
index 000000000000000..edc75d9121776e1
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-fires-to-text-input.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+  </head>
+  <body>
+    <style>
+      #inputscroller {
+        width: 100px;
+        height: 50px;
+      }
+    </style>
+    <input type="text" id="inputscroller"
+    value="qwertyuiopasddfghjklzxcvbnmqwertyuiopasddfghjklzxcvbnmqwer">
+    <script>
+      promise_test(async() => {
+        const inputscroller = document.getElementById("inputscroller");
+        assert_equals(inputscroller.scrollLeft, 0,
+          "text input field is not initially scrolled.");
+
+        const scrollend_promise = new Promise((resolve) => {
+          inputscroller.addEventListener("scrollend", resolve);
+        });
+        inputscroller.scrollLeft = 10;
+        await scrollend_promise;
+        assert_equals(inputscroller.scrollLeft, 10,
+          "text input field is scrolled by the correct amount");
+      }, "scrolled input field should receive scrollend.");
+    </script>
+  </body>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-user-scroll-common.js b/test/fixtures/wpt/dom/events/scrolling/scrollend-user-scroll-common.js
new file mode 100644
index 000000000000000..1b6372338828435
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-user-scroll-common.js
@@ -0,0 +1,150 @@
+
+async function test_scrollend_on_touch_drag(t, target_div) {
+  // Skip the test on a Mac as they do not support touch screens.
+  const isMac = navigator.platform.toUpperCase().indexOf('MAC') >= 0;
+  if (isMac)
+    return;
+
+  await resetTargetScrollState(t, target_div);
+  await waitForCompositorReady();
+
+  const targetScrollendPromise = waitForScrollendEventNoTimeout(target_div);
+  verifyNoScrollendOnDocument(t);
+
+  let scrollend_count = 0;
+  const scrollend_listener = () => {
+    scrollend_count += 1;
+  };
+  target_div.addEventListener("scrollend", scrollend_listener);
+  t.add_cleanup(() => {
+    target_div.removeEventListener('scrollend', scrollend_listener);
+  });
+
+  // Perform a touch drag on target div and wait for target_div to get
+  // a scrollend event.
+  await new test_driver.Actions()
+    .addPointer('TestPointer', 'touch')
+    .pointerMove(0, 0, { origin: target_div }) // 0, 0 is center of element.
+    .pointerDown()
+    .addTick()
+    .pointerMove(0, -40, { origin: target_div }) //  Drag up to move down.
+    .addTick()
+    .pause(200) //  Prevent inertial scroll.
+    .pointerMove(0, -60, { origin: target_div })
+    .addTick()
+    .pause(200) //  Prevent inertial scroll.
+    .pointerUp()
+    .send();
+
+  await targetScrollendPromise;
+
+  assert_true(target_div.scrollTop > 0);
+  await verifyScrollStopped(t, target_div);
+  assert_equals(scrollend_count, 1);
+}
+
+async function test_scrollend_on_scrollbar_gutter_click(t, target_div) {
+  // Skip test on platforms that do not have a visible scrollbar (e.g.
+  // overlay scrollbar).
+  const scrollbar_width = target_div.offsetWidth - target_div.clientWidth;
+  if (scrollbar_width == 0)
+    return;
+
+  await resetTargetScrollState(t, target_div);
+  await waitForCompositorReady();
+
+  const targetScrollendPromise = waitForScrollendEventNoTimeout(target_div);
+  verifyNoScrollendOnDocument(t);
+
+  const bounds = target_div.getBoundingClientRect();
+  // Some versions of webdriver have been known to frown at non-int arguments
+  // to pointerMove.
+  const x = Math.round(bounds.right - scrollbar_width / 2);
+  const y = Math.round(bounds.bottom - 20);
+  await new test_driver.Actions()
+    .addPointer('TestPointer', 'mouse')
+    .pointerMove(x, y, { origin: 'viewport' })
+    .pointerDown()
+    .addTick()
+    .pointerUp()
+    .send();
+
+  await targetScrollendPromise;
+  assert_true(target_div.scrollTop > 0);
+  await verifyScrollStopped(t, target_div);
+}
+
+// Same issue as previous test.
+async function test_scrollend_on_scrollbar_thumb_drag(t, target_div) {
+  // Skip test on platforms that do not have a visible scrollbar (e.g.
+  // overlay scrollbar).
+  const scrollbar_width = target_div.offsetWidth - target_div.clientWidth;
+  if (scrollbar_width == 0)
+    return;
+
+  await resetTargetScrollState(t, target_div);
+  await waitForCompositorReady();
+
+  const targetScrollendPromise = waitForScrollendEventNoTimeout(target_div);
+  verifyNoScrollendOnDocument(t);
+
+  const bounds = target_div.getBoundingClientRect();
+  // Some versions of webdriver have been known to frown at non-int arguments
+  // to pointerMove.
+  const x = Math.round(bounds.right - scrollbar_width / 2);
+  const y = Math.round(bounds.top + 30);
+  const dy = 30;
+  await new test_driver.Actions()
+    .addPointer('TestPointer', 'mouse')
+    .pointerMove(x, y, { origin: 'viewport' })
+    .pointerDown()
+    .pointerMove(x, y + dy, { origin: 'viewport' })
+    .addTick()
+    .pointerUp()
+    .send();
+
+  await targetScrollendPromise;
+  assert_true(target_div.scrollTop > 0);
+  await verifyScrollStopped(t, target_div);
+}
+
+async function test_scrollend_on_mousewheel_scroll(t, target_div, frame) {
+  await resetTargetScrollState(t, target_div);
+  await waitForCompositorReady();
+
+  const targetScrollendPromise = waitForScrollendEventNoTimeout(target_div);
+  verifyNoScrollendOnDocument(t);
+
+  let scroll_origin = target_div;
+  if (frame) {
+    // chromedriver doesn't support passing { origin: element }
+    // for an element within a subframe. Use the frame element itself.
+    scroll_origin = frame;
+  }
+  const x = 0;
+  const y = 0;
+  const dx = 0;
+  const dy = 40;
+  await new test_driver.Actions()
+  .scroll(x, y, dx, dy, { origin: scroll_origin })
+  .send();
+
+  await targetScrollendPromise;
+  assert_true(target_div.scrollTop > 0);
+  await verifyScrollStopped(t, target_div);
+}
+
+async function test_scrollend_on_keyboard_scroll(t, target_div) {
+  await resetTargetScrollState(t, target_div);
+  await waitForCompositorReady();
+
+  verifyNoScrollendOnDocument(t);
+  const targetScrollendPromise = waitForScrollendEventNoTimeout(target_div);
+
+  target_div.focus();
+  window.test_driver.send_keys(target_div, '\ue015');
+
+  await targetScrollendPromise;
+  assert_true(target_div.scrollTop > 0);
+  await verifyScrollStopped(t, target_div);
+}
diff --git a/test/fixtures/wpt/dom/events/scrolling/scrollend-with-snap-on-fractional-offset.html b/test/fixtures/wpt/dom/events/scrolling/scrollend-with-snap-on-fractional-offset.html
new file mode 100644
index 000000000000000..d1f50304add2ac1
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/scrollend-with-snap-on-fractional-offset.html
@@ -0,0 +1,85 @@
+<!DOCTYPE html>
+<html>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="scroll_support.js"></script>
+  <body>
+    <style>
+      .scroller {
+        scroll-snap-type: x mandatory;
+        overflow-x: auto;
+        overflow-y: hidden;
+        position: relative;
+        height: 500px;
+        width: 500px;
+      }
+
+      .box {
+        scroll-snap-align: start;
+        width: 400px;
+        position: absolute;
+        top: 200px;
+      }
+
+      #box1 {
+        background-color: red;
+        height: 500px;
+      }
+
+      #box2 {
+        background-color: yellow;
+        height: 300px;
+        left: 700.5px;
+      }
+
+      #box3 {
+        background-color: blue;
+        height: 100px;
+        left: 1400px;
+      }
+    </style>
+    <div id="scroller" class="scroller">
+      <div class="box" id="box1">1</div>
+      <div class="box" id="box2">2</div>
+      <div class="box" id="box3">3</div>
+    </div>
+    <script>
+      let scrollendCount = 0;
+      scroller.addEventListener('scrollend', () => {
+        scroller.style.maxHeight = null;
+        scroller.style.maxHeight = `${box2.clientHeight}px`;
+        scrollendCount += 1;
+      });
+      promise_test(async (test) => {
+        // This test aims to verify that scrollend fires correctly (i.e. once)
+        // when the target snap position is not a whole number. In this case, we
+        // expect to snap to the left edge of box2 which is at a fractional
+        // offset from the scroller's origin (left: 700.5px).
+        // The scroll offset resulting from the snap may not be fractional
+        // (e.g. if the browser does not support fractional scroll offsets) so
+        // we verify the scroll offset with assert_approx_equals.
+        assert_equals(scroller.scrollLeft, 0,
+        "test precondition: scroller is not scrolled.");
+        const expected_scroll_left = box2.offsetLeft;
+        const target_offset = box2.offsetLeft + box2.clientWidth / 2;
+
+        let scrollend_promise = waitForScrollendEvent(test, scroller);
+        scroller.scrollTo( { left: target_offset });
+        await scrollend_promise;
+
+        // Instead of a time-based wait for errant scrollends, we wait a frame
+        // and then scroll back to 0.
+        await waitForCompositorCommit();
+        assert_approx_equals(scroller.scrollLeft, expected_scroll_left, 1,
+            "scroller snaps to the left edge of box 2");
+
+        scrollend_promise = waitForScrollendEvent(test, scroller);
+        scroller.scrollTo({ left: 0 });
+        await scrollend_promise;
+        assert_equals(scroller.scrollLeft, 0,
+            "scroller should be scrolled back to 0.");
+        assert_equals(scrollendCount, 2, "exactly 2 scrollends should be seen");
+      }, "snap to fractional offset fires scrollend exactly once.");
+    </script>
+  </body>
+</html>
\ No newline at end of file
diff --git a/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-basic.html b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-basic.html
new file mode 100644
index 000000000000000..1b9df69ec77f883
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-basic.html
@@ -0,0 +1,140 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<meta name="variant" content="?include=target-basic"/>
+<meta name="variant" content="?include=scroll-over-scrollable-child"/>
+<meta name="variant" content="?include=transaction-not-bound-to-scroll-frame"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/common/subset-tests-by-key.js"></script>
+<script src="scroll_support.js"></script>
+<style>
+body {
+  margin: 0;
+  padding: 0;
+  height: 200vh;
+}
+
+.spacer {
+  width: 100%;
+  height: 25px;
+  padding: 0;
+  margin: 0;
+}
+
+#scrollableDiv {
+  width: 100%;
+  height: 500px;
+  overflow: scroll;
+  background: yellow;
+}
+
+#innerDiv {
+  width: 100%;
+  height: 4000px;
+  background: red;
+}
+
+</style>
+<head>
+<body onload=runTest()>
+<div id="firstRootSpacer" class="spacer" style="background: cyan"></div>
+<div id="secondRootSpacer" class="spacer" style="background: magenta"></div>
+<div id="scrollableDiv">
+  <div id="innerDiv">
+    <div id="firstInnerSpacer" class="spacer" style="background: green">
+    </div>
+    <div id="secondInnerSpacer" class="spacer" style="background: blue">
+    </div>
+  </div>
+</div>
+</body>
+
+<script>
+
+let variants = [
+  // Ensure that the wheel transaction fires all wheel events to the initial
+  // target.
+  {
+    key: 'target-basic',
+    origin: "viewport",
+    scrollX: 40,
+    scrollY: 2,
+    scrollingElement: document.scrollingElement,
+    targetElement: firstRootSpacer,
+    title: 'Wheel events should be captured to one target #1',
+  },
+  // Ensure that the wheel transaction fires all wheel events to the initial
+  // target, even when another scroll frame is under the mouse cursor.
+  {
+    key: 'scroll-over-scrollable-child',
+    origin: "viewport",
+    scrollX: 40,
+    scrollY: 27,
+    scrollingElement: document.scrollingElement,
+    targetElement: secondRootSpacer,
+    title: 'Wheel events should be captured to one target #2',
+  },
+  // Ensure that the wheel transaction targets the topmost-element, which is
+  // not the scrollable element.
+  {
+    key: 'transaction-not-bound-to-scroll-frame',
+    origin: innerDiv,
+    scrollX: 40,
+    scrollY: 2,
+    scrollingElement: scrollableDiv,
+    targetElement: innerDiv,
+    title: 'The wheel event transactions target may not be a scroll frame',
+  },
+];
+
+function runTest() {
+  async function testBasic(testInfo, t) {
+    await waitForCompositorReady();
+
+    await waitForCompositorCommit();
+
+    let wheelEventTargets = [];
+    function pushTargetToWheelEventTargets(e) {
+      wheelEventTargets.push(e.target)
+    }
+
+    window.addEventListener("wheel", pushTargetToWheelEventTargets, {passive: true});
+
+    // Scroll past the boundary of the original element to ensure all events in
+    // transaction have the same target.
+    await new test_driver.Actions()
+      .addWheel("wheel1")
+      .scroll(testInfo.scrollX, testInfo.scrollY, 0, 30, {origin: testInfo.origin})
+      .pause(1)
+      .scroll(testInfo.scrollX, testInfo.scrollY, 0, 30, {origin: testInfo.origin})
+      .pause(1)
+      .scroll(testInfo.scrollX, testInfo.scrollY, 0, 30, {origin: testInfo.origin})
+      .send();
+
+    // TODO(dlrobertson): Use the scrollend event here to wait for the
+    // wheel scroll to finish instead of waitForAnimationEnd().
+    await waitForAnimationEnd(() => { return testInfo.scrollingElement.scrollTop; });
+    await waitForCompositorCommit();
+
+    // Ensure that all the captured wheel events are the expected target.
+    wheelEventTargets.forEach((wheelEventTarget, i) => {
+      assert_equals(wheelEventTarget, testInfo.targetElement,
+                    "Wheel event at index `" + i + "` does not have the expected target");
+    });
+
+    assert_greater_than(testInfo.scrollingElement.scrollTop, 0,
+                        "The scrolling element has scrolled");
+  }
+
+  variants.forEach((testInfo) => {
+    subsetTestByKey(testInfo.key, promise_test, t => testBasic(testInfo, t), testInfo.title);
+  });
+}
+</script>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-multiple-action-chains.html b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-multiple-action-chains.html
new file mode 100644
index 000000000000000..3b46b2f99a9c994
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-multiple-action-chains.html
@@ -0,0 +1,101 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="scroll_support.js"></script>
+<style>
+body {
+  margin: 0;
+  padding: 0;
+  height: 200vh;
+}
+
+#initial {
+  background: red;
+  width: 100%;
+  height: 25px;
+  padding: 0;
+  margin: 0;
+}
+
+#second {
+  background: green;
+  width: 100%;
+  height: 200vh;
+  padding: 0;
+  margin: 0;
+}
+
+</style>
+<head>
+<body>
+<div id="initial"></div>
+<div id="second"></div>
+</body>
+
+<script>
+
+promise_test(async (t) => {
+  await new Promise(resolve => addEventListener("load", resolve, {once: true}));
+
+  await waitForCompositorReady();
+
+  await waitForCompositorCommit();
+
+  let firstEventTargets = [];
+  let secondEventTargets = [];
+  let isFirstGroup = true;
+  window.addEventListener("wheel", (e) => {
+    if (isFirstGroup) {
+      firstEventTargets.push(e.target);
+    } else {
+      secondEventTargets.push(e.target);
+    }
+  }, {passive: true});
+
+  await waitForCompositorCommit();
+
+  // The first action chain should target the initial element
+  await new test_driver.Actions()
+    .addWheel("wheel1")
+    .scroll(40, 2, 0, 30, {origin: "viewport"})
+    .send();
+
+  // Start logging event targets in the second transaction
+  isFirstGroup = false;
+
+  // The second chain should target the second element and the prior wheel event
+  // group should have no impact on this action chain.
+  await new test_driver.Actions()
+    .addWheel("wheel1")
+    .scroll(40, 30, 0, 30, {origin: "viewport"})
+    .send();
+
+  // TODO(dlrobertson): Use the scrollend event here to wait for the
+  // wheel scroll to finish instead of waitForAnimationEnd().
+  await waitForAnimationEnd(() => { return document.scrollingElement.scrollTop; });
+  await waitForCompositorCommit();
+
+  assert_greater_than(firstEventTargets.length, 0,
+                      "There should be at least one event in the first transaction");
+  assert_greater_than(secondEventTargets.length, 0,
+                      "There should be at least one event in the second transaction");
+
+  firstEventTargets.forEach((wheelEventTarget, i) => {
+    assert_equals(wheelEventTarget, initial,
+                  "Wheel event at index `" + i + "` did not target the initial element");
+  });
+
+  secondEventTargets.forEach((wheelEventTarget, i) => {
+    assert_equals(wheelEventTarget, second,
+                  "Wheel event at index `" + i + "` did not target the second element");
+  });
+}, "Two separate webdriver action chains should have different wheel event transactions");
+</script>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-display-change.html b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-display-change.html
new file mode 100644
index 000000000000000..6ca3c78b74cefe8
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-display-change.html
@@ -0,0 +1,100 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<meta name="variant" content="?include=none"/>
+<meta name="variant" content="?include=contents"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/common/subset-tests-by-key.js"></script>
+<script src="scroll_support.js"></script>
+<style>
+body {
+  margin: 0;
+  padding: 0;
+  height: 200vh;
+}
+
+.spacer {
+  width: 100%;
+  height: 25px;
+  padding: 0;
+  margin: 0;
+}
+
+</style>
+<head>
+<body onload=runTest()>
+<div id="initialTarget" class="spacer" style="background: red"></div>
+<div id="firstRootSpacer" class="spacer" style="background: green"></div>
+<div id="secondRootSpacer" class="spacer" style="background: blue"></div>
+</body>
+
+<script>
+
+let variants = [
+  "none",
+  "contents",
+]
+
+function runTest() {
+  async function testDisplayChange(display, t) {
+    await waitForCompositorReady();
+
+    await waitForCompositorCommit();
+
+    let wheelEventTargets = [];
+    let makeInitialTargetNone = false;
+
+    // Modify the initial element the wheel event is targetted at to
+    // display: <variant> once we fire the first wheel event, then log
+    // the subsequent wheel event targets.
+    function makeInitialElementNone(e) {
+      wheelEventTargets.push(e.target);
+      if (!makeInitialTargetNone) {
+        makeInitialTargetNone = true;
+        e.target.style.display = display;
+      }
+    }
+    window.addEventListener("wheel", makeInitialElementNone, {passive: true});
+
+    await waitForCompositorCommit();
+
+    await new test_driver.Actions()
+      .addWheel("wheel1")
+      .scroll(40, 2, 0, 30, {origin: "viewport"})
+      .pause(1)
+      .scroll(40, 2, 0, 30, {origin: "viewport"})
+      .send();
+
+    // TODO(dlrobertson): Use the scrollend event here to wait for the
+    // wheel scroll to finish instead of waitForAnimationEnd().
+    await waitForAnimationEnd(() => { return document.scrollingElement.scrollTop; });
+    await waitForCompositorCommit();
+
+    // The first wheel event should be targetted at the modified element.
+    assert_equals(wheelEventTargets.shift(), initialTarget,
+                  "Initial wheel event is has the modified element as the target");
+
+    wheelEventTargets.forEach((wheelEventTarget, i) => {
+      // TODO(dlrobertson): This assertion is pretty weak, but browsers seem to disagree
+      // on what element the event should target. Find out what the target should be here
+      // and make this assertion more restrictive.
+      assert_not_equals(wheelEventTarget, initialTarget,
+                        "Wheel event at index `" + i + "` targetted the initial element");
+    });
+
+    assert_greater_than(document.scrollingElement.scrollTop, 0, "The document has scrolled");
+  }
+
+  variants.forEach((variant) => {
+    subsetTestByKey(variant, promise_test, t => testDisplayChange(variant, t),
+                    "Modify the initial wheel event target to display:" + variant);
+  });
+}
+</script>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-elements.html b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-elements.html
new file mode 100644
index 000000000000000..0109b7b6b18b924
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-elements.html
@@ -0,0 +1,74 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<link rel="stylesheet" type="text/css" href="/fonts/ahem.css"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="scroll_support.js"></script>
+<style>
+body {
+  margin: 0;
+  padding: 0;
+  height: 200vh;
+}
+
+.spacer {
+  width: 100%;
+  height: 25px;
+  padding: 0;
+  margin: 0;
+  font: 25px/1 Ahem;
+}
+
+</style>
+<head>
+<body>
+<div id="firstRootSpacer" class="spacer" style="background: green">X</div>
+<div id="secondRootSpacer" class="spacer" style="background: blue"></div>
+</body>
+
+<script>
+
+promise_test(async (t) => {
+  // Wheel event transactions target elements, not nodes. A wheel event
+  // transaction that begins over a text node should have an event target for
+  // the containing element.
+  await waitForCompositorReady();
+
+  await waitForCompositorCommit();
+
+  let wheelEventTargets = [];
+
+  window.addEventListener("wheel", (e) => {
+    wheelEventTargets.push(e.target);
+  }, {passive: true});
+
+  await waitForCompositorCommit();
+
+  await new test_driver.Actions()
+    .addWheel("wheel1")
+    .scroll(12, 12, 0, 30, {origin: "viewport"})
+    .pause(1)
+    .scroll(12, 12, 0, 30, {origin: "viewport"})
+    .send();
+
+  // TODO(dlrobertson): Use the scrollend event here to wait for the
+  // wheel scroll to finish instead of waitForAnimationEnd().
+  await waitForAnimationEnd(() => { return document.scrollingElement.scrollTop; });
+  await waitForCompositorCommit();
+
+  // All of the wheel events should have the first div as their target.
+  wheelEventTargets.forEach((wheelEventTarget, i) => {
+    assert_equals(wheelEventTarget, firstRootSpacer,
+                  "Wheel event at index `" + i + "` does not have the expected target");
+  });
+
+  assert_greater_than(document.scrollingElement.scrollTop, 0, "The document has scrolled");
+}, "Wheel event transactions target elements");
+</script>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-move.html b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-move.html
new file mode 100644
index 000000000000000..a739d1cd5479ad5
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-move.html
@@ -0,0 +1,85 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="scroll_support.js"></script>
+<style>
+body {
+  margin: 0;
+  padding: 0;
+  height: 200vh;
+}
+
+.spacer {
+  width: 100%;
+  height: 25px;
+  padding: 0;
+  margin: 0;
+}
+
+</style>
+<head>
+<body>
+<div id="initialTarget" class="spacer" style="background: red"></div>
+<div id="firstRootSpacer" class="spacer" style="background: green"></div>
+<div id="secondRootSpacer" class="spacer" style="background: blue"></div>
+</body>
+
+<script>
+
+promise_test(async (t) => {
+  await new Promise(resolve => addEventListener("load", resolve, {once: true}));
+
+  await waitForCompositorReady();
+
+  await waitForCompositorCommit();
+
+  let wheelEventTargets = [];
+  let movedInitialTarget = false;
+
+  // Move the initial element the wheel event is targetted at once we fire the
+  // first wheel event, then log the subsequent wheel event targets.
+  function moveInitialElement(e) {
+    wheelEventTargets.push(e.target);
+    if (!movedInitialTarget) {
+      movedInitialTarget = true;
+      secondRootSpacer.insertAdjacentElement('afterend', e.target);
+    }
+  }
+  window.addEventListener("wheel", moveInitialElement, {passive: true});
+
+  await waitForCompositorCommit();
+
+  await new test_driver.Actions()
+    .addWheel("wheel1")
+    .scroll(40, 2, 0, 30, {origin: "viewport"})
+    .pause(1)
+    .scroll(40, 2, 0, 30, {origin: "viewport"})
+    .send();
+
+  // TODO(dlrobertson): Use the scrollend event here to wait for the
+  // wheel scroll to finish instead of waitForAnimationEnd().
+  await waitForAnimationEnd(() => { return document.scrollingElement.scrollTop; });
+  await waitForCompositorCommit();
+
+  // The first wheel event should be targetted at the moved element.
+  assert_equals(wheelEventTargets.shift(), initialTarget,
+                "Initial wheel event has the moved element as the target");
+
+  wheelEventTargets.forEach((wheelEventTarget, i) => {
+    // TODO(dlrobertson): This assertion is pretty weak, but browsers seem to disagree
+    // on what element the event should target. Find out what the target should be here
+    // and make this assertion more restrictive.
+    assert_not_equals(wheelEventTarget, initialTarget,
+                      "Wheel event at index `" + i + "` targetted the initial element");
+  });
+  assert_greater_than(document.scrollingElement.scrollTop, 0, "The document has scrolled");
+}, "Move the initial wheel event target.");
+</script>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-removal.html b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-removal.html
new file mode 100644
index 000000000000000..f81efd22e22b92d
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-removal.html
@@ -0,0 +1,92 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="scroll_support.js"></script>
+<style>
+body {
+  margin: 0;
+  padding: 0;
+  height: 200vh;
+}
+
+.spacer {
+  width: 100%;
+  height: 25px;
+  padding: 0;
+  margin: 0;
+}
+
+</style>
+<head>
+<body>
+<div id="initialTarget" class="spacer" style="background: red"></div>
+<div id="firstRootSpacer" class="spacer" style="background: green"></div>
+<div id="secondRootSpacer" class="spacer" style="background: blue"></div>
+</body>
+
+<script>
+
+promise_test(async (t) => {
+  await new Promise(resolve => addEventListener("load", resolve, {once: true}));
+
+  await waitForCompositorReady();
+
+  await waitForCompositorCommit();
+
+
+  let initialTarget = null;
+  let wheelEventTargets = [];
+  let removedInitialTarget = false;
+
+  // Remove the initial element the wheel event is targetted at once we fire the
+  // first wheel event, then log the subsequent wheel event targets.
+  function removeInitialElement(e) {
+    wheelEventTargets.push(e.target);
+    if (!removedInitialTarget) {
+      initialTarget = e.target;
+      e.target.remove();
+      removedInitialTarget = true;
+      initialTarget.addEventListener("wheel", () => {
+        assert_true(false, "wheel event should never be fired after the target is removed")
+      }, {passive: true});
+    }
+  }
+  window.addEventListener("wheel", removeInitialElement, {passive: true});
+
+  await waitForCompositorCommit();
+
+  await new test_driver.Actions()
+    .addWheel("wheel1")
+    .scroll(40, 2, 0, 30, {origin: "viewport"})
+    .pause(1)
+    .scroll(40, 2, 0, 30, {origin: "viewport"})
+    .send();
+
+  // TODO(dlrobertson): Use the scrollend event here to wait for the
+  // wheel scroll to finish instead of waitForAnimationEnd().
+  await waitForAnimationEnd(() => { return document.scrollingElement.scrollTop; });
+  await waitForCompositorCommit();
+
+  assert_true(removedInitialTarget, "Removed the initial target");
+  // The first wheel event should be targetted at the removed element.
+  assert_equals(wheelEventTargets.shift(), initialTarget,
+                "Initial wheel event has the removed element as the target");
+
+  wheelEventTargets.forEach((wheelEventTarget, i) => {
+    // TODO(dlrobertson): This assertion is pretty weak, but browsers seem to disagree
+    // on what element the event should target. Find out what the target should be here
+    // and make this assertion more restrictive.
+    assert_not_equals(wheelEventTarget, initialTarget,
+                      "Wheel event at index `" + i + "` targetted the initial element");
+  });
+  assert_greater_than(document.scrollingElement.scrollTop, 0, "The document has scrolled");
+}, "Remove the initial wheel event target.");
+</script>
+</html>
diff --git a/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-resize.html b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-resize.html
new file mode 100644
index 000000000000000..eb7431fca475db3
--- /dev/null
+++ b/test/fixtures/wpt/dom/events/scrolling/wheel-event-transactions-target-resize.html
@@ -0,0 +1,97 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1">
+<meta name="variant" content="?include=passive-false"/>
+<meta name="variant" content="?include=passive-true"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/common/subset-tests-by-key.js"></script>
+<script src="scroll_support.js"></script>
+<style>
+body {
+  margin: 0;
+  padding: 0;
+  height: 200vh;
+}
+
+.spacer {
+  width: 100%;
+  height: 25px;
+  padding: 0;
+  margin: 0;
+}
+
+</style>
+<head>
+<body onload=runTest()>
+<div id="initialTarget" class="spacer" style="background: red"></div>
+<div id="firstRootSpacer" class="spacer" style="background: green"></div>
+<div id="secondRootSpacer" class="spacer" style="background: blue"></div>
+</body>
+
+<script>
+
+let variants = [
+  {
+    key: "passive-false",
+    passive: false,
+  },
+  {
+    key: "passive-true",
+    passive: true,
+  },
+];
+
+function runTest() {
+  async function testResizeTarget(passive, t) {
+    await waitForCompositorReady();
+
+    await waitForCompositorCommit();
+
+    let wheelEventTargets = [];
+    let resizedInitialTarget = false;
+
+    // Resize the initial element the wheel event is targetted at once we fire the
+    // first wheel event, then log the subsequent wheel event targets.
+    function resizeInitialElement(e) {
+      wheelEventTargets.push(e.target);
+      if (!resizedInitialTarget) {
+        resizedInitialTarget = true;
+        e.target.style.height = '10px';
+      }
+    }
+    window.addEventListener("wheel", resizeInitialElement, {passive: passive});
+
+    await waitForCompositorCommit();
+
+    await new test_driver.Actions()
+      .addWheel("wheel1")
+      .scroll(2, 2, 0, 30, {origin: "viewport"})
+      .pause(1)
+      .scroll(2, 2, 0, 30, {origin: "viewport"})
+      .send();
+
+    // TODO(dlrobertson): Use the scrollend event here to wait for the
+    // wheel scroll to finish instead of waitForAnimationEnd().
+    await waitForAnimationEnd(() => { return document.scrollingElement.scrollTop; });
+    await waitForCompositorCommit();
+
+    wheelEventTargets.forEach((wheelEventTarget, i) => {
+      assert_equals(wheelEventTarget, initialTarget,
+                    "Wheel event at `" + i + "` does not match the expected target")
+    });
+    assert_greater_than(document.scrollingElement.scrollTop, 0, "The document has scrolled");
+  }
+
+  variants.forEach((variant) => {
+    subsetTestByKey(variant.key, promise_test, t => testResizeTarget(variant.passive, t),
+                    "Resize the initial target and use a passive:" + variant.passive + " listener");
+  });
+}
+</script>
+</html>
diff --git a/test/fixtures/wpt/hr-time/raf-coarsened-time.https.html b/test/fixtures/wpt/hr-time/raf-coarsened-time.https.html
new file mode 100644
index 000000000000000..182c707dc3b783c
--- /dev/null
+++ b/test/fixtures/wpt/hr-time/raf-coarsened-time.https.html
@@ -0,0 +1,36 @@
+<!doctype html>
+<html>
+<head>
+  <link rel="help" href="https://html.spec.whatwg.org/multipage/webappapis.html#update-the-rendering">
+  <script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+    /* Coarsen to 5 microseconds or coarser */
+    const COARSE_RESOLUTION = 0.005;
+
+    const CUSTOM_TIMELINE_DELTA = 0.002;
+    const FLOATING_POINT_ERROR_EPSILON = 0.01;
+
+    // Note that this test would fail if the platform introduces a jitter.
+    // It is recommended that platforms that implement jitter run this test
+    // with a flag that turns jitter off, if possible.
+
+    const customTimeline = new DocumentTimeline({originTime: CUSTOM_TIMELINE_DELTA});
+    promise_test(async t => {
+        for (let i = 0; i < 32; ++i) {
+            const timestamp = await new Promise(resolve => requestAnimationFrame(ts => resolve(ts)));
+            const coarse_timestamp = Math.round(timestamp / COARSE_RESOLUTION) * COARSE_RESOLUTION;
+            assert_approx_equals(timestamp, coarse_timestamp, FLOATING_POINT_ERROR_EPSILON,
+              "timestamp should be coarsened");
+            assert_approx_equals(timestamp, document.timeline.currentTime, FLOATING_POINT_ERROR_EPSILON,
+              "document.timeline.currentTimeline should be the same as the rAF callback");
+            assert_approx_equals(customTimeline.currentTime + CUSTOM_TIMELINE_DELTA,
+              timestamp, FLOATING_POINT_ERROR_EPSILON,
+              "originTime for custom timeline should not be coarsened");
+        }
+    });
+</script>
+</body>
+</html>
diff --git a/test/fixtures/wpt/hr-time/raf-coarsened-time.https.html.headers b/test/fixtures/wpt/hr-time/raf-coarsened-time.https.html.headers
new file mode 100644
index 000000000000000..5f8621ef83660c6
--- /dev/null
+++ b/test/fixtures/wpt/hr-time/raf-coarsened-time.https.html.headers
@@ -0,0 +1,2 @@
+Cross-Origin-Embedder-Policy: require-corp
+Cross-Origin-Opener-Policy: same-origin
diff --git a/test/fixtures/wpt/html/webappapis/microtask-queuing/queue-microtask-cross-realm-callback-report-exception.html b/test/fixtures/wpt/html/webappapis/microtask-queuing/queue-microtask-cross-realm-callback-report-exception.html
new file mode 100644
index 000000000000000..fa153f8f965d2be
--- /dev/null
+++ b/test/fixtures/wpt/html/webappapis/microtask-queuing/queue-microtask-cross-realm-callback-report-exception.html
@@ -0,0 +1,28 @@
+<!doctype html>
+<meta charset=utf-8>
+<title>queueMicrotask() reports the exception from its callback in the callback's global object</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<iframe></iframe>
+<iframe></iframe>
+<iframe></iframe>
+<script>
+setup({ allow_uncaught_exception: true });
+
+const onerrorCalls = [];
+window.onerror = () => { onerrorCalls.push("top"); };
+frames[0].onerror = () => { onerrorCalls.push("frame0"); };
+frames[1].onerror = () => { onerrorCalls.push("frame1"); };
+frames[2].onerror = () => { onerrorCalls.push("frame2"); };
+
+async_test(t => {
+  window.onload = t.step_func(() => {
+    frames[0].queueMicrotask(new frames[1].Function(`throw new parent.frames[2].Error("PASS");`));
+
+    t.step_timeout(() => {
+      assert_array_equals(onerrorCalls, ["frame1"]);
+      t.done();
+    }, 4);
+  });
+});
+</script>
diff --git a/test/fixtures/wpt/html/webappapis/structured-clone/WEB_FEATURES.yml b/test/fixtures/wpt/html/webappapis/structured-clone/WEB_FEATURES.yml
new file mode 100644
index 000000000000000..423a469bf17283e
--- /dev/null
+++ b/test/fixtures/wpt/html/webappapis/structured-clone/WEB_FEATURES.yml
@@ -0,0 +1,3 @@
+features:
+- name: structured-clone
+  files: "**"
diff --git a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests-harness.js b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests-harness.js
index 660477dca4c621f..00a86fa74b9a968 100644
--- a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests-harness.js
+++ b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests-harness.js
@@ -9,6 +9,7 @@
  * - `postTest()`: An optional, async function run after a test is done
  * - `structuredClone(obj, transferList)`: Required function that somehow
  *                                         structurally clones an object.
+ *                                         Must return a promise.
  * - `hasDocument`: When true, disables tests that require a document. True by default.
  */
 
@@ -30,11 +31,11 @@ function runStructuredCloneBatteryOfTests(runner) {
     }
 
     return new Promise(resolve => {
-      promise_test(async _ => {
+      promise_test(async t => {
         test = await test;
         await setupPromise;
         await runner.preTest(test);
-        await test.f(runner)
+        await test.f(runner, t)
         await runner.postTest(test);
         resolve();
       }, test.description);
diff --git a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests-with-transferables.js b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests-with-transferables.js
index 744f1168196001f..23cf4f651ac70ae 100644
--- a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests-with-transferables.js
+++ b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests-with-transferables.js
@@ -20,3 +20,150 @@ structuredCloneBatteryOfTests.push({
 });
 
 // TODO: ImageBitmap
+
+structuredCloneBatteryOfTests.push({
+  description: 'A detached ArrayBuffer cannot be transferred',
+  async f(runner, t) {
+    const buffer = new ArrayBuffer();
+    await runner.structuredClone(buffer, [buffer]);
+    await promise_rejects_dom(
+      t,
+      "DataCloneError",
+      runner.structuredClone(buffer, [buffer])
+    );
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'A detached platform object cannot be transferred',
+  async f(runner, t) {
+    const {port1} = new MessageChannel();
+    await runner.structuredClone(port1, [port1]);
+    await promise_rejects_dom(
+      t,
+      "DataCloneError",
+      runner.structuredClone(port1, [port1])
+    );
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'Transferring a non-transferable platform object fails',
+  async f(runner, t) {
+    const blob = new Blob();
+    await promise_rejects_dom(
+      t,
+      "DataCloneError",
+      runner.structuredClone(blob, [blob])
+    );
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'An object whose interface is deleted from the global object must still be received',
+  async f(runner) {
+    const {port1} = new MessageChannel();
+    const messagePortInterface = globalThis.MessagePort;
+    delete globalThis.MessagePort;
+    try {
+      const transfer = await runner.structuredClone(port1, [port1]);
+      assert_true(transfer instanceof messagePortInterface);
+    } finally {
+      globalThis.MessagePort = messagePortInterface;
+    }
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'A subclass instance will be received as its closest transferable superclass',
+  async f(runner) {
+    // MessagePort doesn't have a constructor, so we must use something else.
+
+    // Make sure that ReadableStream is transferable before we test its subclasses.
+    try {
+      const stream = new ReadableStream();
+      await runner.structuredClone(stream, [stream]);
+    } catch(err) {
+      if (err instanceof DOMException && err.code === DOMException.DATA_CLONE_ERR) {
+        throw new OptionalFeatureUnsupportedError("ReadableStream isn't transferable");
+      } else {
+        throw err;
+      }
+    }
+
+    class ReadableStreamSubclass extends ReadableStream {}
+    const original = new ReadableStreamSubclass();
+    const transfer = await runner.structuredClone(original, [original]);
+    assert_equals(Object.getPrototypeOf(transfer), ReadableStream.prototype);
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'Resizable ArrayBuffer is transferable',
+  async f(runner) {
+    const buffer = new ArrayBuffer(16, { maxByteLength: 1024 });
+    const copy = await runner.structuredClone(buffer, [buffer]);
+    assert_equals(buffer.byteLength, 0);
+    assert_equals(copy.byteLength, 16);
+    assert_equals(copy.maxByteLength, 1024);
+    assert_true(copy.resizable);
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'Length-tracking TypedArray is transferable',
+  async f(runner) {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    const ta = new Uint8Array(ab);
+    const copy = await runner.structuredClone(ta, [ab]);
+    assert_equals(ab.byteLength, 0);
+    assert_equals(copy.buffer.byteLength, 16);
+    assert_equals(copy.buffer.maxByteLength, 1024);
+    assert_true(copy.buffer.resizable);
+    copy.buffer.resize(32);
+    assert_equals(copy.byteLength, 32);
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'Length-tracking DataView is transferable',
+  async f(runner) {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    const dv = new DataView(ab);
+    const copy = await runner.structuredClone(dv, [ab]);
+    assert_equals(ab.byteLength, 0);
+    assert_equals(copy.buffer.byteLength, 16);
+    assert_equals(copy.buffer.maxByteLength, 1024);
+    assert_true(copy.buffer.resizable);
+    copy.buffer.resize(32);
+    assert_equals(copy.byteLength, 32);
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'Transferring OOB TypedArray throws',
+  async f(runner, t) {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    const ta = new Uint8Array(ab, 8);
+    ab.resize(0);
+    await promise_rejects_dom(
+      t,
+      "DataCloneError",
+      runner.structuredClone(ta, [ab])
+    );
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'Transferring OOB DataView throws',
+  async f(runner, t) {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    const dv = new DataView(ab, 8);
+    ab.resize(0);
+    await promise_rejects_dom(
+      t,
+      "DataCloneError",
+      runner.structuredClone(dv, [ab])
+    );
+  }
+});
diff --git a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests.js b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests.js
index 0c96ded2088357e..923ac9dc1649189 100644
--- a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests.js
+++ b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-battery-of-tests.js
@@ -3,11 +3,6 @@
 structuredCloneBatteryOfTests = [];
 
 function check(description, input, callback, requiresDocument = false) {
-  testObjMock = {
-    done() {},
-    step_func(f) {return _ => f()},
-  };
-
   structuredCloneBatteryOfTests.push({
     description,
     async f(runner) {
@@ -16,47 +11,41 @@ function check(description, input, callback, requiresDocument = false) {
         newInput = input();
       }
       const copy = await runner.structuredClone(newInput);
-      await callback(copy, newInput, testObjMock);
+      await callback(copy, newInput);
     },
     requiresDocument
   });
 }
 
-function compare_primitive(actual, input, test_obj) {
+function compare_primitive(actual, input) {
   assert_equals(actual, input);
-  if (test_obj)
-    test_obj.done();
 }
-function compare_Array(callback, callback_is_async) {
-  return function(actual, input, test_obj) {
+function compare_Array(callback) {
+  return async function(actual, input) {
     if (typeof actual === 'string')
       assert_unreached(actual);
     assert_true(actual instanceof Array, 'instanceof Array');
     assert_not_equals(actual, input);
     assert_equals(actual.length, input.length, 'length');
-    callback(actual, input);
-    if (test_obj && !callback_is_async)
-      test_obj.done();
+    await callback(actual, input);
   }
 }
 
-function compare_Object(callback, callback_is_async) {
-  return function(actual, input, test_obj) {
+function compare_Object(callback) {
+  return async function(actual, input) {
     if (typeof actual === 'string')
       assert_unreached(actual);
     assert_true(actual instanceof Object, 'instanceof Object');
     assert_false(actual instanceof Array, 'instanceof Array');
     assert_not_equals(actual, input);
-    callback(actual, input);
-    if (test_obj && !callback_is_async)
-      test_obj.done();
+    await callback(actual, input);
   }
 }
 
-function enumerate_props(compare_func, test_obj) {
-  return function(actual, input) {
+function enumerate_props(compare_func) {
+  return async function(actual, input) {
     for (const x in input) {
-      compare_func(actual[x], input[x], test_obj);
+      await compare_func(actual[x], input[x]);
     }
   };
 }
@@ -127,14 +116,12 @@ check('Object primitives', {'undefined':undefined,
                            '9007199254740994':9007199254740994,
                            '-9007199254740994':-9007199254740994}, compare_Object(enumerate_props(compare_primitive)));
 
-function compare_Boolean(actual, input, test_obj) {
+function compare_Boolean(actual, input) {
   if (typeof actual === 'string')
     assert_unreached(actual);
   assert_true(actual instanceof Boolean, 'instanceof Boolean');
   assert_equals(String(actual), String(input), 'converted to primitive');
   assert_not_equals(actual, input);
-  if (test_obj)
-    test_obj.done();
 }
 check('Boolean true', new Boolean(true), compare_Boolean);
 check('Boolean false', new Boolean(false), compare_Boolean);
@@ -143,14 +130,12 @@ check('Object Boolean objects', {'true':new Boolean(true), 'false':new Boolean(f
 
 function compare_obj(what) {
   const Type = self[what];
-  return function(actual, input, test_obj) {
+  return function(actual, input) {
     if (typeof actual === 'string')
       assert_unreached(actual);
     assert_true(actual instanceof Type, 'instanceof '+what);
     assert_equals(Type(actual), Type(input), 'converted to primitive');
     assert_not_equals(actual, input);
-    if (test_obj)
-      test_obj.done();
   };
 }
 check('String empty string', new String(''), compare_obj('String'));
@@ -203,14 +188,12 @@ check('Object Number objects', {'0.2':new Number(0.2),
                                '9007199254740994':new Number(9007199254740994),
                                '-9007199254740994':new Number(-9007199254740994)}, compare_Object(enumerate_props(compare_obj('Number'))));
 
-function compare_Date(actual, input, test_obj) {
+function compare_Date(actual, input) {
   if (typeof actual === 'string')
     assert_unreached(actual);
   assert_true(actual instanceof Date, 'instanceof Date');
   assert_equals(Number(actual), Number(input), 'converted to primitive');
   assert_not_equals(actual, input);
-  if (test_obj)
-    test_obj.done();
 }
 check('Date 0', new Date(0), compare_Date);
 check('Date -0', new Date(-0), compare_Date);
@@ -227,7 +210,7 @@ check('Object Date objects', {'0':new Date(0),
 
 function compare_RegExp(expected_source) {
   // XXX ES6 spec doesn't define exact serialization for `source` (it allows several ways to escape)
-  return function(actual, input, test_obj) {
+  return function(actual, input) {
     if (typeof actual === 'string')
       assert_unreached(actual);
     assert_true(actual instanceof RegExp, 'instanceof RegExp');
@@ -239,8 +222,6 @@ function compare_RegExp(expected_source) {
     assert_equals(actual.unicode, input.unicode, 'unicode');
     assert_equals(actual.lastIndex, 0, 'lastIndex');
     assert_not_equals(actual, input);
-    if (test_obj)
-      test_obj.done();
   }
 }
 function func_RegExp_flags_lastIndex() {
@@ -273,7 +254,28 @@ check('Object RegExp object, RegExp empty', {'x':new RegExp('')}, compare_Object
 check('Object RegExp object, RegExp slash', {'x':new RegExp('/')}, compare_Object(enumerate_props(compare_RegExp('\\/'))));
 check('Object RegExp object, RegExp new line', {'x':new RegExp('\n')}, compare_Object(enumerate_props(compare_RegExp('\\n'))));
 
-async function compare_Blob(actual, input, test_obj, expect_File) {
+function compare_Error(actual, input) {
+  assert_true(actual instanceof Error, "Checking instanceof");
+  assert_equals(actual.constructor, input.constructor, "Checking constructor");
+  assert_equals(actual.name, input.name, "Checking name");
+  assert_equals(actual.hasOwnProperty("message"), input.hasOwnProperty("message"), "Checking message existence");
+  assert_equals(actual.message, input.message, "Checking message");
+  assert_equals(actual.foo, undefined, "Checking for absence of custom property");
+}
+
+check('Empty Error object', new Error, compare_Error);
+
+const errorConstructors = [Error, EvalError, RangeError, ReferenceError,
+                           SyntaxError, TypeError, URIError];
+for (const constructor of errorConstructors) {
+  check(`${constructor.name} object`, () => {
+    let error = new constructor("Error message here");
+    error.foo = "testing";
+    return error;
+  }, compare_Error);
+}
+
+async function compare_Blob(actual, input, expect_File) {
   if (typeof actual === 'string')
     assert_unreached(actual);
   assert_true(actual instanceof Blob, 'instanceof Blob');
@@ -333,33 +335,33 @@ function func_Blob_NUL() {
 }
 check('Blob NUL', func_Blob_NUL, compare_Blob);
 
-check('Array Blob object, Blob basic', [func_Blob_basic()], compare_Array(enumerate_props(compare_Blob), true));
-check('Array Blob object, Blob unpaired high surrogate (invalid utf-8)', [func_Blob_bytes([0xD800])()], compare_Array(enumerate_props(compare_Blob), true));
-check('Array Blob object, Blob unpaired low surrogate (invalid utf-8)', [func_Blob_bytes([0xDC00])()], compare_Array(enumerate_props(compare_Blob), true));
-check('Array Blob object, Blob paired surrogates (invalid utf-8)', [func_Blob_bytes([0xD800, 0xDC00])()], compare_Array(enumerate_props(compare_Blob), true));
-check('Array Blob object, Blob empty', [func_Blob_empty()], compare_Array(enumerate_props(compare_Blob), true));
-check('Array Blob object, Blob NUL', [func_Blob_NUL()], compare_Array(enumerate_props(compare_Blob), true));
-check('Array Blob object, two Blobs', [func_Blob_basic(), func_Blob_empty()], compare_Array(enumerate_props(compare_Blob), true));
-
-check('Object Blob object, Blob basic', {'x':func_Blob_basic()}, compare_Object(enumerate_props(compare_Blob), true));
-check('Object Blob object, Blob unpaired high surrogate (invalid utf-8)', {'x':func_Blob_bytes([0xD800])()}, compare_Object(enumerate_props(compare_Blob), true));
-check('Object Blob object, Blob unpaired low surrogate (invalid utf-8)', {'x':func_Blob_bytes([0xDC00])()}, compare_Object(enumerate_props(compare_Blob), true));
-check('Object Blob object, Blob paired surrogates (invalid utf-8)', {'x':func_Blob_bytes([0xD800, 0xDC00])()  }, compare_Object(enumerate_props(compare_Blob), true));
-check('Object Blob object, Blob empty', {'x':func_Blob_empty()}, compare_Object(enumerate_props(compare_Blob), true));
-check('Object Blob object, Blob NUL', {'x':func_Blob_NUL()}, compare_Object(enumerate_props(compare_Blob), true));
-
-function compare_File(actual, input, test_obj) {
+check('Array Blob object, Blob basic', [func_Blob_basic()], compare_Array(enumerate_props(compare_Blob)));
+check('Array Blob object, Blob unpaired high surrogate (invalid utf-8)', [func_Blob_bytes([0xD800])()], compare_Array(enumerate_props(compare_Blob)));
+check('Array Blob object, Blob unpaired low surrogate (invalid utf-8)', [func_Blob_bytes([0xDC00])()], compare_Array(enumerate_props(compare_Blob)));
+check('Array Blob object, Blob paired surrogates (invalid utf-8)', [func_Blob_bytes([0xD800, 0xDC00])()], compare_Array(enumerate_props(compare_Blob)));
+check('Array Blob object, Blob empty', [func_Blob_empty()], compare_Array(enumerate_props(compare_Blob)));
+check('Array Blob object, Blob NUL', [func_Blob_NUL()], compare_Array(enumerate_props(compare_Blob)));
+check('Array Blob object, two Blobs', [func_Blob_basic(), func_Blob_empty()], compare_Array(enumerate_props(compare_Blob)));
+
+check('Object Blob object, Blob basic', {'x':func_Blob_basic()}, compare_Object(enumerate_props(compare_Blob)));
+check('Object Blob object, Blob unpaired high surrogate (invalid utf-8)', {'x':func_Blob_bytes([0xD800])()}, compare_Object(enumerate_props(compare_Blob)));
+check('Object Blob object, Blob unpaired low surrogate (invalid utf-8)', {'x':func_Blob_bytes([0xDC00])()}, compare_Object(enumerate_props(compare_Blob)));
+check('Object Blob object, Blob paired surrogates (invalid utf-8)', {'x':func_Blob_bytes([0xD800, 0xDC00])()  }, compare_Object(enumerate_props(compare_Blob)));
+check('Object Blob object, Blob empty', {'x':func_Blob_empty()}, compare_Object(enumerate_props(compare_Blob)));
+check('Object Blob object, Blob NUL', {'x':func_Blob_NUL()}, compare_Object(enumerate_props(compare_Blob)));
+
+async function compare_File(actual, input) {
   assert_true(actual instanceof File, 'instanceof File');
   assert_equals(actual.name, input.name, 'name');
   assert_equals(actual.lastModified, input.lastModified, 'lastModified');
-  compare_Blob(actual, input, test_obj, true);
+  await compare_Blob(actual, input, true);
 }
 function func_File_basic() {
   return new File(['foo'], 'bar', {type:'text/x-bar', lastModified:42});
 }
 check('File basic', func_File_basic, compare_File);
 
-function compare_FileList(actual, input, test_obj) {
+function compare_FileList(actual, input) {
   if (typeof actual === 'string')
     assert_unreached(actual);
   assert_true(actual instanceof FileList, 'instanceof FileList');
@@ -367,8 +369,6 @@ function compare_FileList(actual, input, test_obj) {
   assert_not_equals(actual, input);
   // XXX when there's a way to populate or construct a FileList,
   // check the items in the FileList
-  if (test_obj)
-    test_obj.done();
 }
 function func_FileList_empty() {
   const input = document.createElement('input');
@@ -379,30 +379,36 @@ check('FileList empty', func_FileList_empty, compare_FileList, true);
 check('Array FileList object, FileList empty', () => ([func_FileList_empty()]), compare_Array(enumerate_props(compare_FileList)), true);
 check('Object FileList object, FileList empty', () => ({'x':func_FileList_empty()}), compare_Object(enumerate_props(compare_FileList)), true);
 
+function compare_ArrayBuffer(actual, input) {
+  assert_true(actual instanceof ArrayBuffer, 'instanceof ArrayBuffer');
+  assert_equals(actual.byteLength, input.byteLength, 'byteLength');
+  assert_equals(actual.maxByteLength, input.maxByteLength, 'maxByteLength');
+  assert_equals(actual.resizable, input.resizable, 'resizable');
+  assert_equals(actual.growable, input.growable, 'growable');
+}
+
 function compare_ArrayBufferView(view) {
   const Type = self[view];
-  return function(actual, input, test_obj) {
+  return function(actual, input) {
     if (typeof actual === 'string')
       assert_unreached(actual);
     assert_true(actual instanceof Type, 'instanceof '+view);
     assert_equals(actual.length, input.length, 'length');
+    assert_equals(actual.byteLength, input.byteLength, 'byteLength');
+    assert_equals(actual.byteOffset, input.byteOffset, 'byteOffset');
     assert_not_equals(actual.buffer, input.buffer, 'buffer');
     for (let i = 0; i < actual.length; ++i) {
       assert_equals(actual[i], input[i], 'actual['+i+']');
     }
-    if (test_obj)
-      test_obj.done();
   };
 }
-function compare_ImageData(actual, input, test_obj) {
+function compare_ImageData(actual, input) {
   if (typeof actual === 'string')
     assert_unreached(actual);
   assert_equals(actual.width, input.width, 'width');
   assert_equals(actual.height, input.height, 'height');
   assert_not_equals(actual.data, input.data, 'data');
   compare_ArrayBufferView('Uint8ClampedArray')(actual.data, input.data, null);
-  if (test_obj)
-    test_obj.done();
 }
 function func_ImageData_1x1_transparent_black() {
   const canvas = document.createElement('canvas');
@@ -506,6 +512,23 @@ check('Object with non-configurable property', function() {
   return rv;
 }, compare_Object(check_configurable_property('foo')));
 
+structuredCloneBatteryOfTests.push({
+  description: 'Object with a getter that throws',
+  async f(runner, t) {
+    const exception = new Error();
+    const testObject = {
+      get testProperty() {
+        throw exception;
+      }
+    };
+    await promise_rejects_exactly(
+      t,
+      exception,
+      runner.structuredClone(testObject)
+    );
+  }
+});
+
 /* The tests below are inspired by @zcorpan’s work but got some
 more substantial changed due to their previous async setup */
 
@@ -616,3 +639,115 @@ check('ObjectPrototype must lose its exotic-ness when cloned',
     assert_equals(Object.getPrototypeOf(copy), newProto);
   }
 );
+
+structuredCloneBatteryOfTests.push({
+  description: 'Serializing a non-serializable platform object fails',
+  async f(runner, t) {
+    const request = new Response();
+    await promise_rejects_dom(
+      t,
+      "DataCloneError",
+      runner.structuredClone(request)
+    );
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'An object whose interface is deleted from the global must still deserialize',
+  async f(runner) {
+    const blob = new Blob();
+    const blobInterface = globalThis.Blob;
+    delete globalThis.Blob;
+    try {
+      const copy = await runner.structuredClone(blob);
+      assert_true(copy instanceof blobInterface);
+    } finally {
+      globalThis.Blob = blobInterface;
+    }
+  }
+});
+
+check(
+  'A subclass instance will deserialize as its closest serializable superclass',
+  () => {
+    class FileSubclass extends File {}
+    return new FileSubclass([], "");
+  },
+  (copy) => {
+    assert_equals(Object.getPrototypeOf(copy), File.prototype);
+  }
+);
+
+check(
+  'Resizable ArrayBuffer',
+  () => {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    assert_true(ab.resizable);
+    return ab;
+  },
+  compare_ArrayBuffer);
+
+structuredCloneBatteryOfTests.push({
+  description: 'Growable SharedArrayBuffer',
+  async f(runner) {
+    const sab = createBuffer('SharedArrayBuffer', 16, { maxByteLength: 1024 });
+    assert_true(sab.growable);
+    try {
+      const copy = await runner.structuredClone(sab);
+      compare_ArrayBuffer(sab, copy);
+    } catch (e) {
+      // If we're cross-origin isolated, cloning SABs should not fail.
+      if (e instanceof DOMException && e.code === DOMException.DATA_CLONE_ERR) {
+        assert_false(self.crossOriginIsolated);
+      } else {
+        throw e;
+      }
+    }
+  }
+});
+
+check(
+  'Length-tracking TypedArray',
+  () => {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    assert_true(ab.resizable);
+    return new Uint8Array(ab);
+  },
+  compare_ArrayBufferView('Uint8Array'));
+
+check(
+  'Length-tracking DataView',
+  () => {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    assert_true(ab.resizable);
+    return new DataView(ab);
+  },
+  compare_ArrayBufferView('DataView'));
+
+structuredCloneBatteryOfTests.push({
+  description: 'Serializing OOB TypedArray throws',
+  async f(runner, t) {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    const ta = new Uint8Array(ab, 8);
+    ab.resize(0);
+    await promise_rejects_dom(
+      t,
+      "DataCloneError",
+      runner.structuredClone(ta)
+    );
+  }
+});
+
+structuredCloneBatteryOfTests.push({
+  description: 'Serializing OOB DataView throws',
+  async f(runner, t) {
+    const ab = new ArrayBuffer(16, { maxByteLength: 1024 });
+    const dv = new DataView(ab, 8);
+    ab.resize(0);
+    await promise_rejects_dom(
+      t,
+      "DataCloneError",
+      runner.structuredClone(dv)
+    );
+  }
+});
diff --git a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-cross-realm-method.html b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-cross-realm-method.html
new file mode 100644
index 000000000000000..d80010e0df78ad7
--- /dev/null
+++ b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-cross-realm-method.html
@@ -0,0 +1,20 @@
+<!doctype html>
+<title>self.structuredClone() uses this's relevant Realm for deserialization</title>
+<link rel="help" href="https://html.spec.whatwg.org/multipage/structured-data.html#structured-cloning">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<body>
+<script>
+const iframe = document.createElement("iframe");
+iframe.onload = () => {
+  const otherWindow = iframe.contentWindow;
+  for (const key of ["Object", "Array", "Date", "RegExp"]) {
+    test(() => {
+      const cloned = otherWindow.structuredClone.call(window, new otherWindow[key]);
+      assert_true(cloned instanceof window[key]);
+    }, `${key} instance`);
+  }
+};
+document.body.append(iframe);
+</script>
diff --git a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-detached-window-crash.html b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-detached-window-crash.html
new file mode 100644
index 000000000000000..75971023d2d79f1
--- /dev/null
+++ b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone-detached-window-crash.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<title>window.structuredClone() doesn't crash when window is detached</title>
+<link rel="help" href="https://crbug.com/1445375">
+<body>
+<script>
+let i = document.createElement("iframe");
+document.body.appendChild(i);
+let i_win = i.contentWindow;
+i.remove();
+i_win.structuredClone("some data");
+</script>
diff --git a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone.any.js b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone.any.js
index 34f96f33fdf8812..1358a71fc03d4e0 100644
--- a/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone.any.js
+++ b/test/fixtures/wpt/html/webappapis/structured-clone/structured-clone.any.js
@@ -1,9 +1,14 @@
 // META: title=structuredClone() tests
+// META: script=/common/sab.js
 // META: script=/html/webappapis/structured-clone/structured-clone-battery-of-tests.js
 // META: script=/html/webappapis/structured-clone/structured-clone-battery-of-tests-with-transferables.js
 // META: script=/html/webappapis/structured-clone/structured-clone-battery-of-tests-harness.js
 
 runStructuredCloneBatteryOfTests({
-  structuredClone: (obj, transfer) => self.structuredClone(obj, { transfer }),
+  structuredClone: (obj, transfer) => {
+    return new Promise(resolve => {
+      resolve(self.structuredClone(obj, { transfer }));
+    });
+  },
   hasDocument: typeof document !== "undefined",
 });
diff --git a/test/fixtures/wpt/html/webappapis/timers/clearinterval-from-callback.any.js b/test/fixtures/wpt/html/webappapis/timers/clearinterval-from-callback.any.js
new file mode 100644
index 000000000000000..bf4eb7cf5ac897f
--- /dev/null
+++ b/test/fixtures/wpt/html/webappapis/timers/clearinterval-from-callback.any.js
@@ -0,0 +1,19 @@
+async_test((t) => {
+  let wasPreviouslyCalled = false;
+
+  const handle = setInterval(
+    t.step_func(() => {
+      if (!wasPreviouslyCalled) {
+        wasPreviouslyCalled = true;
+
+        clearInterval(handle);
+
+        // Make the test succeed after the callback would've run next.
+        setInterval(t.step_func_done(), 750);
+      } else {
+        assert_unreached();
+      }
+    }),
+    500
+  );
+}, "Clearing an interval from the callback should still clear it.");
diff --git a/test/fixtures/wpt/html/webappapis/timers/evil-spec-example.any.js b/test/fixtures/wpt/html/webappapis/timers/evil-spec-example.any.js
new file mode 100644
index 000000000000000..17215e218a9e26e
--- /dev/null
+++ b/test/fixtures/wpt/html/webappapis/timers/evil-spec-example.any.js
@@ -0,0 +1,12 @@
+var t = async_test("Interaction of setTimeout and WebIDL")
+function finishTest() {
+  assert_equals(log, "ONE TWO ")
+  t.done()
+}
+var log = '';
+function logger(s) { log += s + ' '; }
+
+setTimeout({ toString: function () {
+  setTimeout("logger('ONE')", 100);
+  return "logger('TWO'); t.step(finishTest)";
+} }, 100);
diff --git a/test/fixtures/wpt/html/webappapis/timers/evil-spec-example.html b/test/fixtures/wpt/html/webappapis/timers/evil-spec-example.html
deleted file mode 100644
index 77a8746908d7425..000000000000000
--- a/test/fixtures/wpt/html/webappapis/timers/evil-spec-example.html
+++ /dev/null
@@ -1,23 +0,0 @@
-<!doctype html>
-<title>Interaction of setTimeout and WebIDL</title>
-<link rel="author" title="Ian Hickson" href="mailto:ian@hixie.ch">
-<link rel="author" title="Ms2ger" href="mailto:ms2ger@gmail.com">
-<link rel="help" href="https://html.spec.whatwg.org/multipage/#dom-windowtimers-settimeout">
-<link rel="help" href="https://heycam.github.io/webidl/#es-operations">
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<div id="log"></div>
-<script>
-var t = async_test()
-function finishTest() {
-  assert_equals(log, "ONE TWO ")
-  t.done()
-}
-var log = '';
-function logger(s) { log += s + ' '; }
-
-setTimeout({ toString: function () {
-  setTimeout("logger('ONE')", 100);
-  return "logger('TWO'); t.step(finishTest)";
-} }, 100);
-</script>
diff --git a/test/fixtures/wpt/html/webappapis/timers/setinterval-cross-realm-callback-report-exception.html b/test/fixtures/wpt/html/webappapis/timers/setinterval-cross-realm-callback-report-exception.html
new file mode 100644
index 000000000000000..4a780fc93291b15
--- /dev/null
+++ b/test/fixtures/wpt/html/webappapis/timers/setinterval-cross-realm-callback-report-exception.html
@@ -0,0 +1,32 @@
+<!doctype html>
+<meta charset=utf-8>
+<title>window.setInterval() reports the exception from its callback in the callback's global object</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<iframe></iframe>
+<iframe></iframe>
+<iframe></iframe>
+<script>
+setup({ allow_uncaught_exception: true });
+
+const onerrorCalls = [];
+window.onerror = () => { onerrorCalls.push("top"); };
+frames[0].onerror = () => { onerrorCalls.push("frame0"); };
+frames[1].onerror = () => { onerrorCalls.push("frame1"); };
+frames[2].onerror = () => { onerrorCalls.push("frame2"); };
+
+async_test(t => {
+  window.onload = t.step_func(() => {
+    const id = frames[0].setInterval(new frames[1].Function(`
+      parent.clearThisInterval();
+      throw new parent.frames[2].Error("PASS");
+    `), 4);
+    window.clearThisInterval = () => { frames[0].clearInterval(id); };
+
+    t.step_timeout(() => {
+      assert_array_equals(onerrorCalls, ["frame1"]);
+      t.done();
+    }, 8);
+  });
+});
+</script>
diff --git a/test/fixtures/wpt/html/webappapis/timers/settimeout-cross-realm-callback-report-exception.html b/test/fixtures/wpt/html/webappapis/timers/settimeout-cross-realm-callback-report-exception.html
new file mode 100644
index 000000000000000..b4860151a6c39f9
--- /dev/null
+++ b/test/fixtures/wpt/html/webappapis/timers/settimeout-cross-realm-callback-report-exception.html
@@ -0,0 +1,28 @@
+<!doctype html>
+<meta charset=utf-8>
+<title>window.setTimeout() reports the exception from its callback in the callback's global object</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<iframe></iframe>
+<iframe></iframe>
+<iframe></iframe>
+<script>
+setup({ allow_uncaught_exception: true });
+
+const onerrorCalls = [];
+window.onerror = () => { onerrorCalls.push("top"); };
+frames[0].onerror = () => { onerrorCalls.push("frame0"); };
+frames[1].onerror = () => { onerrorCalls.push("frame1"); };
+frames[2].onerror = () => { onerrorCalls.push("frame2"); };
+
+async_test(t => {
+  window.onload = t.step_func(() => {
+    frames[0].setTimeout(new frames[1].Function(`throw new parent.frames[2].Error("PASS");`), 4);
+
+    t.step_timeout(() => {
+      assert_array_equals(onerrorCalls, ["frame1"]);
+      t.done();
+    }, 8);
+  });
+});
+</script>
diff --git a/test/fixtures/wpt/interfaces/dom.idl b/test/fixtures/wpt/interfaces/dom.idl
index 72d61f5cfd80ad4..99192924f4f46f9 100644
--- a/test/fixtures/wpt/interfaces/dom.idl
+++ b/test/fixtures/wpt/interfaces/dom.idl
@@ -120,9 +120,9 @@ interface mixin ParentNode {
   readonly attribute Element? lastElementChild;
   readonly attribute unsigned long childElementCount;
 
-  [CEReactions, Unscopable] undefined prepend((Node or TrustedScript or DOMString)... nodes);
-  [CEReactions, Unscopable] undefined append((Node or TrustedScript or DOMString)... nodes);
-  [CEReactions, Unscopable] undefined replaceChildren((Node or TrustedScript or DOMString)... nodes);
+  [CEReactions, Unscopable] undefined prepend((Node or DOMString)... nodes);
+  [CEReactions, Unscopable] undefined append((Node or DOMString)... nodes);
+  [CEReactions, Unscopable] undefined replaceChildren((Node or DOMString)... nodes);
 
   Element? querySelector(DOMString selectors);
   [NewObject] NodeList querySelectorAll(DOMString selectors);
@@ -139,9 +139,9 @@ Element includes NonDocumentTypeChildNode;
 CharacterData includes NonDocumentTypeChildNode;
 
 interface mixin ChildNode {
-  [CEReactions, Unscopable] undefined before((Node or TrustedScript or DOMString)... nodes);
-  [CEReactions, Unscopable] undefined after((Node or TrustedScript or DOMString)... nodes);
-  [CEReactions, Unscopable] undefined replaceWith((Node or TrustedScript or DOMString)... nodes);
+  [CEReactions, Unscopable] undefined before((Node or DOMString)... nodes);
+  [CEReactions, Unscopable] undefined after((Node or DOMString)... nodes);
+  [CEReactions, Unscopable] undefined replaceWith((Node or DOMString)... nodes);
   [CEReactions, Unscopable] undefined remove();
 };
 DocumentType includes ChildNode;
diff --git a/test/fixtures/wpt/interfaces/html.idl b/test/fixtures/wpt/interfaces/html.idl
index 4d6c0229bc13925..f7ad9ac2ddead5d 100644
--- a/test/fixtures/wpt/interfaces/html.idl
+++ b/test/fixtures/wpt/interfaces/html.idl
@@ -1411,8 +1411,6 @@ interface mixin CanvasDrawPath {
 interface mixin CanvasUserInterface {
   undefined drawFocusIfNeeded(Element element);
   undefined drawFocusIfNeeded(Path2D path, Element element);
-  undefined scrollPathIntoView();
-  undefined scrollPathIntoView(Path2D path);
 };
 
 interface mixin CanvasText {
diff --git a/test/fixtures/wpt/performance-timeline/back-forward-cache-restoration.tentative.html b/test/fixtures/wpt/performance-timeline/back-forward-cache-restoration.tentative.html
new file mode 100644
index 000000000000000..c673e09cb461e09
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/back-forward-cache-restoration.tentative.html
@@ -0,0 +1,95 @@
+<!doctype html>
+<html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/common/utils.js"></script>
+  <script src="/common/dispatcher/dispatcher.js"></script>
+  <script src="/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js"></script>
+</head>
+
+<body>
+  <script>
+    const BackForwardCacheRestorationName = '';
+    const BackForwardCacheRestorationType = 'back-forward-cache-restoration';
+
+    let getNavigationId = (i) => {
+      let identifier = 'mark' + i;
+      performance.mark(identifier);
+      return window.performance.getEntriesByName(identifier)[0].navigationId;
+    }
+
+    let getNumberofBackForwardCacheRestorationEntries = (BackForwardCacheRestorationType) => {
+      return window.performance.getEntriesByType(BackForwardCacheRestorationType).length;
+    }
+
+    let getBackForwardCacheRestorationByType = (BackForwardCacheRestorationType) => {
+      let entries = window.performance.getEntriesByType(BackForwardCacheRestorationType);
+      return entries[entries.length - 1];
+    }
+
+    let getBackForwardCacheRestorationByGetAllAndFilter = (BackForwardCacheRestorationType) => {
+      let entries = window.performance.getEntries().filter(e => e.entryType == BackForwardCacheRestorationType);
+      return entries[entries.length - 1];
+    }
+
+    let getBackForwardCacheRestorationByPerformanceObserverBuffered = async (BackForwardCacheRestorationType) => {
+      let p = new Promise(resolve => {
+        new PerformanceObserver((list) => {
+          const entries = list.getEntries().filter(e => e.entryType == BackForwardCacheRestorationType);
+          if (entries.length > 0) {
+            resolve(entries[entries.length - 1]);
+          }
+        }).observe({ type: BackForwardCacheRestorationType, buffered: true });
+      });
+      return await p;
+    }
+
+    let checkEntry = (entry, previousNavigationId) => {
+      assert_equals(entry.name, BackForwardCacheRestorationName);
+      assert_equals(entry.entryType, BackForwardCacheRestorationType);
+      assert_not_equals(entry.navigationId, previousNavigationId);
+      assert_true(entry.pageshowEventStart > entry.startTime);
+      assert_true(entry.pageshowEventEnd >= entry.pageshowEventStart);
+    }
+
+    promise_test(async t => {
+      const pageA = new RemoteContext(token());
+      const pageB = new RemoteContext(token());
+
+      const urlA = executorPath + pageA.context_id;
+      const urlB = originCrossSite + executorPath + pageB.context_id;
+      // Open url A.
+      window.open(urlA, '_blank', 'noopener');
+      await pageA.execute_script(waitForPageShow);
+
+      // Assert no instance of BackForwardCacheRestoration exists without back forward cache navigatoin.
+      let size = await pageA.execute_script(getNumberofBackForwardCacheRestorationEntries);
+      assert_equals(0, size);
+
+      let entry;
+      for (i = 0; i < 2; i++) {
+        let curr_nav_id = await pageA.execute_script(getNavigationId, [i]);
+
+        // Navigate away to url B and back.
+        await navigateAndThenBack(pageA, pageB, urlB);
+
+        // Assert Performance Observer API supports BackForwardCacheRestoration.
+        entry = await pageA.execute_script(getBackForwardCacheRestorationByPerformanceObserverBuffered, [BackForwardCacheRestorationType]);
+        // The navigation id after a bfcache restoration should be different
+        // from that before.
+        checkEntry(entry, curr_nav_id);
+
+        // Assert Performance Timeline API supports BackForwardCacheRestoration.
+        entry = await pageA.execute_script(getBackForwardCacheRestorationByType, [BackForwardCacheRestorationType]);
+        checkEntry(entry, curr_nav_id);
+
+        entry = await pageA.execute_script(getBackForwardCacheRestorationByGetAllAndFilter, [BackForwardCacheRestorationType]);
+        checkEntry(entry, curr_nav_id);
+      }
+    }, 'Performance API for the back forward cache restoration entry.');
+  </script>
+</body>
+
+</html>
diff --git a/test/fixtures/wpt/performance-timeline/droppedentriescount.any.js b/test/fixtures/wpt/performance-timeline/droppedentriescount.any.js
new file mode 100644
index 000000000000000..4de816bdc42bd8f
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/droppedentriescount.any.js
@@ -0,0 +1,81 @@
+promise_test(t => {
+  // This setup is required for later tests as well.
+  // Await for a dropped entry.
+  return new Promise(res => {
+    // Set a buffer size of 0 so that new resource entries count as dropped.
+    performance.setResourceTimingBufferSize(0);
+    // Use an observer to make sure the promise is resolved only when the
+    // new entry has been created.
+    new PerformanceObserver(res).observe({type: 'resource'});
+    fetch('resources/square.png?id=1');
+  }).then(() => {
+  return new Promise(resolve => {
+    new PerformanceObserver(t.step_func((entries, obs, options) => {
+      assert_equals(options['droppedEntriesCount'], 0);
+      resolve();
+    })).observe({type: 'mark'});
+    performance.mark('test');
+  })});
+}, 'Dropped entries count is 0 when there are no dropped entries of relevant type.');
+
+promise_test(async t => {
+  return new Promise(resolve => {
+    new PerformanceObserver(t.step_func((entries, obs, options) => {
+      assert_equals(options['droppedEntriesCount'], 1);
+      resolve();
+    })).observe({entryTypes: ['mark', 'resource']});
+    performance.mark('meow');
+  });
+}, 'Dropped entries correctly counted with multiple types.');
+
+promise_test(t => {
+  return new Promise(resolve => {
+    new PerformanceObserver(t.step_func((entries, obs, options) => {
+      assert_equals(options['droppedEntriesCount'], 1,
+          'There should have been some dropped resource timing entries at this point');
+      resolve();
+    })).observe({type: 'resource', buffered: true});
+  });
+}, 'Dropped entries counted even if observer was not registered at the time.');
+
+promise_test(t => {
+  return new Promise(resolve => {
+    let callback_ran = false;
+    new PerformanceObserver(t.step_func((entries, obs, options) => {
+      if (!callback_ran) {
+        assert_equals(options['droppedEntriesCount'], 2,
+            'There should be two dropped entries right now.');
+        fetch('resources/square.png?id=3');
+        callback_ran = true;
+      } else {
+        assert_equals(options['droppedEntriesCount'], undefined,
+            'droppedEntriesCount should be unset after the first callback!');
+        resolve();
+      }
+    })).observe({type: 'resource'});
+    fetch('resources/square.png?id=2');
+  });
+}, 'Dropped entries only surfaced on the first callback.');
+
+
+promise_test(t => {
+  return new Promise(resolve => {
+    let callback_ran = false;
+    let droppedEntriesCount = -1;
+    new PerformanceObserver(t.step_func((entries, obs, options) => {
+      if (!callback_ran) {
+        assert_greater_than(options['droppedEntriesCount'], 0,
+            'There should be several dropped entries right now.');
+        droppedEntriesCount = options['droppedEntriesCount'];
+        callback_ran = true;
+        obs.observe({type: 'mark'});
+        performance.mark('woof');
+      } else {
+        assert_equals(options['droppedEntriesCount'], droppedEntriesCount,
+            'There should be droppedEntriesCount due to the new observe().');
+        resolve();
+      }
+    })).observe({type: 'resource'});
+    fetch('resources/square.png?id=4');
+  });
+}, 'Dropped entries surfaced after an observe() call!');
diff --git a/test/fixtures/wpt/performance-timeline/idlharness-shadowrealm.window.js b/test/fixtures/wpt/performance-timeline/idlharness-shadowrealm.window.js
new file mode 100644
index 000000000000000..6caaa3306132bdc
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/idlharness-shadowrealm.window.js
@@ -0,0 +1,2 @@
+// META: script=/resources/idlharness-shadowrealm.js
+idl_test_shadowrealm(["performance-timeline"], ["hr-time", "dom"]);
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id-detached-frame.tentative.html b/test/fixtures/wpt/performance-timeline/navigation-id-detached-frame.tentative.html
new file mode 100644
index 000000000000000..add11255af45c00
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id-detached-frame.tentative.html
@@ -0,0 +1,30 @@
+<!DOCTYPE HTML>
+<html>
+
+<head>
+  <meta charset="utf-8">
+  <title>The navigation_id Detached iframe Parent Page.</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+</head>
+
+<body>
+  <script>
+    promise_test(t => {
+      return new Promise(resolve => {
+        const frame = document.createElement("iframe");
+        frame.addEventListener("load", async () => {
+          // Wait for iframe to be detached.
+          while (frame.contentWindow) {
+            await new Promise(r => t.step_timeout(r, 10));
+          }
+          resolve();
+        });
+        frame.src = "resources/navigation-id-detached-frame-page.html";
+        document.body.appendChild(frame);
+      });
+    }, "The navigation_id getter does not crash a window of detached frame");
+  </script>
+</body>
+
+</html>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id-element-timing.tentative.html b/test/fixtures/wpt/performance-timeline/navigation-id-element-timing.tentative.html
new file mode 100644
index 000000000000000..7ff415530bc69d6
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id-element-timing.tentative.html
@@ -0,0 +1,14 @@
+<!DOCTYPE HTML>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js"></script>
+<script src="navigation-id.helper.js"></script>
+<script>
+  runNavigationIdTest({
+    navigationTimes: 3,
+    testName: 'element_timing',
+  }, "Element Timing navigation id test");
+</script>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id-initial-load.tentative.html b/test/fixtures/wpt/performance-timeline/navigation-id-initial-load.tentative.html
new file mode 100644
index 000000000000000..b996f0f117922d5
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id-initial-load.tentative.html
@@ -0,0 +1,49 @@
+<!DOCTYPE HTML>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<!--
+Navigation timing, LCP and paint timing entries are only emitted during initial
+load, not after a bfcache navigation. Therefore we only verify the existence of
+navigation id, not the increment.
+-->
+
+<body>
+  <p>This text is to trigger a LCP entry emission.</p>
+  <script>
+    async function NavigationIdsFromLCP() {
+      return new Promise(resolve => {
+        new PerformanceObserver((entryList) => {
+          resolve(entryList.getEntries());
+        }).observe({ type: 'largest-contentful-paint', buffered: true });
+      })
+    }
+
+    promise_test(async t => {
+      // Assert navigation id exists in LCP entries and and are all the same.
+      const navigationIdsOfLCP = (await NavigationIdsFromLCP()).map(e => e.navigationId);
+      assert_true(navigationIdsOfLCP.every(e => e == navigationIdsOfLCP[0]),
+        'Navigation Ids of LCP entries should be the same at initial navigation');
+
+      // Assert navigation id exists in a NavigationTiming entry.
+      const navigationIdOfNavigationTiming =
+        performance.getEntriesByType('navigation')[0].navigationId;
+      assert_true(!!navigationIdOfNavigationTiming,
+        'Navigation Id of a navigation timing entry should exist at initial navigation');
+
+      // Assert navigation id exists in PaintTiming entries and are all the same.
+      const navigationIdsOfPaintTiming =
+        performance.getEntriesByType('paint').map(e => e.navigationId);
+      assert_true(navigationIdsOfPaintTiming.every(e =>
+        e == navigationIdsOfPaintTiming[0]),
+        'Navigation Id of PaintTiming entries should be the same as the initial navigation.');
+
+      // Assert navigation ids are all the same.
+      const navigationIdsOfAll =
+        navigationIdsOfLCP.concat(navigationIdsOfPaintTiming, navigationIdOfNavigationTiming);
+      assert_true(navigationIdsOfAll.every(e => e == navigationIdsOfAll[0]),
+        'Navigation Id of all entries should be the same as the initial navigation.');
+
+    }, 'Navigation Ids should exist and are all the same as the initial navigation.');
+  </script>
+</body>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id-long-task-task-attribution.tentative.html b/test/fixtures/wpt/performance-timeline/navigation-id-long-task-task-attribution.tentative.html
new file mode 100644
index 000000000000000..e1da9100aeee55f
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id-long-task-task-attribution.tentative.html
@@ -0,0 +1,14 @@
+<!DOCTYPE HTML>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js"></script>
+<script src="navigation-id.helper.js"></script>
+<script>
+  runNavigationIdTest({
+    navigationTimes: 3,
+    testName: 'long_task_task_attribution',
+  }, "Long Task/Task Attribution navigation id test");
+</script>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id-mark-measure.tentative.html b/test/fixtures/wpt/performance-timeline/navigation-id-mark-measure.tentative.html
new file mode 100644
index 000000000000000..30613ebb980eb01
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id-mark-measure.tentative.html
@@ -0,0 +1,14 @@
+<!DOCTYPE HTML>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js"></script>
+<script src="navigation-id.helper.js"></script>
+<script>
+  runNavigationIdTest({
+    navigationTimes: 3,
+    testName: 'mark_measure',
+  }, "Mark/Measure navigation id test");
+</script>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id-reset.tentative.html b/test/fixtures/wpt/performance-timeline/navigation-id-reset.tentative.html
new file mode 100644
index 000000000000000..f5a2428e5f568ab
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id-reset.tentative.html
@@ -0,0 +1,53 @@
+<!DOCTYPE HTML>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js"></script>
+<script>
+  const reload = () => {
+    window.location.reload();
+  };
+
+  const getNavigationId = () => {
+    window.performance.mark('initial_load');
+    let entries = window.performance.getEntriesByType('mark');
+    return entries[entries.length - 1].navigationId;
+  }
+
+  promise_test(async t => {
+    const pageA = new RemoteContext(token());
+    const pageB = new RemoteContext(token());
+
+    const urlA = executorPath + pageA.context_id;
+    const urlB = originCrossSite + executorPath + pageB.context_id;
+    // Open url A.
+    window.open(urlA, '_blank', 'noopener')
+    await pageA.execute_script(waitForPageShow);
+
+    let navigationIdInitial = await pageA.execute_script(getNavigationId);
+
+    // Navigate away to url B and back.
+    await navigateAndThenBack(pageA, pageB, urlB);
+
+    // Assert navigation id is re-generated and thus different when the
+    // document is load from bfcache.
+    navigationIdAfterBFCacheNav = await pageA.execute_script(getNavigationId);
+    assert_not_equals(navigationIdInitial, navigationIdAfterBFCacheNav, 'Navigation Id should be \
+    re-generated and different from the previous one after back-forward-cache navigation.');
+
+    // Reload page.
+    await pageA.execute_script(reload);
+    await pageA.execute_script(waitForPageShow);
+
+    navigationIdAfterReset = await pageA.execute_script(getNavigationId);
+
+    assert_not_equals(navigationIdAfterReset, navigationIdAfterBFCacheNav, 'Navigation Id should\
+    be re-generated after reload which is different from the previous one.');
+
+    assert_not_equals(navigationIdAfterReset, navigationIdInitial, 'Navigation Id should\
+    be re-generated after reload which is different from the one of the initial load.');
+
+  }, 'Navigation Id should be re-generated after reload.');
+</script>
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id-resource-timing.tentative.html b/test/fixtures/wpt/performance-timeline/navigation-id-resource-timing.tentative.html
new file mode 100644
index 000000000000000..6d0614a6e23940c
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id-resource-timing.tentative.html
@@ -0,0 +1,14 @@
+<!DOCTYPE HTML>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js"></script>
+<script src="navigation-id.helper.js"></script>
+<script>
+  runNavigationIdTest({
+    navigationTimes: 3,
+    testName: 'resource_timing',
+  }, "Resource Timing navigation id test");
+</script>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id-worker-created-entries.html b/test/fixtures/wpt/performance-timeline/navigation-id-worker-created-entries.html
new file mode 100644
index 000000000000000..96fc57be1d426c9
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id-worker-created-entries.html
@@ -0,0 +1,27 @@
+<!doctype html>
+<html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+</head>
+
+<body>
+  <script>
+    promise_test(async () => {
+      const worker = new Worker("resources/worker-navigation-id.js");
+
+      const navigationId = await new Promise(resolve => {
+        worker.onmessage = (e) => {
+          resolve(e.data);
+        };
+        worker.postMessage('');
+      });
+
+      assert_equals(navigationId.length, 0,
+        'Navigation id of performance entries created by a worker should be empty.');
+    }, 'Navigation id of performance entries created by workers should be empty');
+  </script>
+</body>
+
+</html>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/navigation-id.helper.js b/test/fixtures/wpt/performance-timeline/navigation-id.helper.js
new file mode 100644
index 000000000000000..1b72fe9908d573c
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/navigation-id.helper.js
@@ -0,0 +1,144 @@
+// The test functions called in the navigation-counter test. They rely on
+// artifacts defined in
+// '/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js'
+// which should be included before this file to use these functions.
+
+// This function is to obtain navigation ids of all performance entries to
+// verify.
+let testInitial = () => {
+  return window.performance.getEntries().map(e => e.navigationId);
+}
+
+let testMarkMeasure = (markId, markName, MeasureName) => {
+  const markName1 = 'test-mark';
+  const markName2 = 'test-mark' + markId;
+  const measureName = 'test-measure' + markId;
+
+  window.performance.mark(markName1);
+  window.performance.mark(markName2);
+  window.performance.measure(measureName, markName1, markName2);
+  return window.performance.getEntriesByName(markName2).concat(
+    window.performance.getEntriesByName(measureName)).map(e => e.navigationId);
+}
+
+let testResourceTiming = async (resourceTimingEntryId) => {
+  let navigationId;
+
+  let p = new Promise(resolve => {
+    new PerformanceObserver((list) => {
+      const entry = list.getEntries().find(
+        e => e.name.includes('json_resource' + resourceTimingEntryId));
+      if (entry) {
+        navigationId = entry.navigationId;
+        resolve();
+      }
+    }).observe({ type: 'resource' });
+  });
+
+  const resp = await fetch(
+    '/performance-timeline/resources/json_resource' + resourceTimingEntryId + '.json');
+  await p;
+  return [navigationId];
+}
+
+let testElementTiming = async (elementTimingEntryId) => {
+  let navigationId;
+  let p = new Promise(resolve => {
+    new PerformanceObserver((list) => {
+      const entry = list.getEntries().find(
+        e => e.entryType === 'element' && e.identifier === 'test-element-timing' + elementTimingEntryId);
+      if (entry) {
+        navigationId = entry.navigationId;
+        resolve();
+      }
+    }).observe({ type: 'element' });
+  });
+
+  let el = document.createElement('p');
+  el.setAttribute('elementtiming', 'test-element-timing' + elementTimingEntryId);
+  el.textContent = 'test element timing text';
+  document.body.appendChild(el);
+  await p;
+  return [navigationId];
+}
+
+let testLongTask = async () => {
+  let navigationIds = [];
+
+  let p = new Promise(resolve => {
+    new PerformanceObserver((list) => {
+      const entry = list.getEntries().find(e => e.entryType === 'longtask')
+      if (entry) {
+        navigationIds.push(entry.navigationId);
+        navigationIds = navigationIds.concat(
+          entry.attribution.map(a => a.navigationId));
+        resolve();
+      }
+    }).observe({ type: 'longtask' });
+  });
+
+  const script = document.createElement('script');
+  script.src = '/performance-timeline/resources/make_long_task.js';
+  document.body.appendChild(script);
+  await p;
+  document.body.removeChild(script);
+  return navigationIds;
+}
+
+const testFunctionMap = {
+  'mark_measure': testMarkMeasure,
+  'resource_timing': testResourceTiming,
+  'element_timing': testElementTiming,
+  'long_task_task_attribution': testLongTask,
+};
+
+function runNavigationIdTest(params, description) {
+  const defaultParams = {
+    openFunc: url => window.open(url, '_blank', 'noopener'),
+    scripts: [],
+    funcBeforeNavigation: () => { },
+    targetOrigin: originCrossSite,
+    navigationTimes: 4,
+    funcAfterAssertion: () => { },
+  }  // Apply defaults.
+  params = { ...defaultParams, ...params };
+
+  promise_test(async t => {
+    const pageA = new RemoteContext(token());
+    const pageB = new RemoteContext(token());
+
+    const urlA = executorPath + pageA.context_id;
+    const urlB = params.targetOrigin + executorPath + pageB.context_id;
+    // Open url A.
+    params.openFunc(urlA);
+    await pageA.execute_script(waitForPageShow);
+
+    // Assert navigation ids of all performance entries are the same.
+    let navigationIds = await pageA.execute_script(testInitial);
+    assert_true(
+      navigationIds.every(t => t === navigationIds[0]),
+      'Navigation Ids should be the same as the initial load.');
+
+    for (i = 1; i <= params.navigationTimes; i++) {
+      // Navigate away to url B and back.
+      await navigateAndThenBack(pageA, pageB, urlB);
+
+      // Assert new navigation ids are generated when the document is load from bfcache.
+      let nextNavigationIds = await pageA.execute_script(
+        testFunctionMap[params.testName], [i + 1]);
+
+      // Assert navigation ids of all performance entries are the same.
+      assert_true(
+        nextNavigationIds.every(t => t === nextNavigationIds[0]),
+        'All Navigation Ids should be same after bfcache navigation.');
+
+      // Assert navigation ids after bfcache navigation are different from those before.
+      assert_true(
+        navigationIds[0] !== nextNavigationIds[0],
+        params.testName +
+        ' Navigation Ids should be re-generated and different from the previous ones.');
+
+      navigationIds = nextNavigationIds;
+    }
+  }, description);
+}
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/abort-block-bfcache.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/abort-block-bfcache.window.js
new file mode 100644
index 000000000000000..e5dbb0f43c8dd3d
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/abort-block-bfcache.window.js
@@ -0,0 +1,21 @@
+// META: title=Aborting a parser should block bfcache
+// META: script=./test-helper.js
+// META: timeout=long
+
+
+async_test(t => {
+  if (!sessionStorage.getItem("pageVisited")) {
+    // This is the first time loading the page.
+    sessionStorage.setItem("pageVisited", 1);
+    t.step_timeout(() => {
+        // Go to another page and instantly come back to this page.
+        location.href = new URL("../resources/going-back.html", window.location);
+    }, 0);
+    // Abort parsing in the middle of loading the page.
+    window.stop();
+  } else {
+    const nrr = performance.getEntriesByType('navigation')[0].notRestoredReasons;
+    assert_true(ReasonsInclude(nrr.reasons, "parser-aborted"));
+    t.done();
+  }
+}, "aborting a parser should block bfcache.");
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-attributes.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-attributes.tentative.window.js
new file mode 100644
index 000000000000000..44495fa981b7520
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-attributes.tentative.window.js
@@ -0,0 +1,55 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+'use strict';
+
+// Ensure that empty attributes are reported as empty strings and missing
+// attributes are reported as null.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+  // Add a cross-origin iframe.
+  const rc1_child = await rc1.addIframe(
+      /*extraConfig=*/ {
+        origin: 'HTTP_REMOTE_ORIGIN',
+        scripts: [],
+        headers: [],
+      },
+      /*attributes=*/ {id: '', name: ''},
+  );
+  // Use WebSocket to block BFCache.
+  await useWebSocket(rc1);
+  const rc1_child_url = await rc1_child.executeScript(() => {
+    return location.href;
+  });
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[{'reason': 'websocket'}],
+      /*children=*/[{
+        'url': null,
+        'src': rc1_child_url,
+        // Id and name should be empty.
+        'id': '',
+        'name': '',
+        'reasons': null,
+        'children': null
+      }]);
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-bfcache-reasons-stay.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-bfcache-reasons-stay.tentative.window.js
new file mode 100644
index 000000000000000..28dbc38575a3b26
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-bfcache-reasons-stay.tentative.window.js
@@ -0,0 +1,47 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+'use strict';
+
+// Ensure that notRestoredReasons are only updated after non BFCache navigation.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  // Use WebSocket to block BFCache.
+  await useWebSocket(rc1);
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[{'reason': 'websocket'}],
+      /*children=*/ []);
+
+  // This time no blocking feature is used, so the page is restored
+  // from BFCache. Ensure that the previous reasons stay there.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ true);
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[{'reason': 'websocket'}],
+      /*children=*/ []);
+});
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-bfcache.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-bfcache.tentative.window.js
new file mode 100644
index 000000000000000..bfb685451c36d6d
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-bfcache.tentative.window.js
@@ -0,0 +1,28 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: timeout=long
+
+'use strict';
+
+// Ensure that notRestoredReasons is empty for successful BFCache restore.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+
+  // Check the BFCache result and verify that no reasons are recorded
+  // for successful restore.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ true);
+  assert_true(await rc1.executeScript(() => {
+    let reasons =
+        performance.getEntriesByType('navigation')[0].notRestoredReasons;
+    return reasons === null;
+  }));
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-cross-origin-bfcache.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-cross-origin-bfcache.tentative.window.js
new file mode 100644
index 000000000000000..2a313fe7b14334c
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-cross-origin-bfcache.tentative.window.js
@@ -0,0 +1,60 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+'use strict';
+
+// Ensure that cross-origin subtree's reasons are not exposed to
+// notRestoredReasons.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+  // Add a cross-origin iframe.
+  const rc1_child = await rc1.addIframe(
+      /*extraConfig=*/ {
+        origin: 'HTTP_REMOTE_ORIGIN',
+        scripts: [],
+        headers: [],
+      },
+      /*attributes=*/ {id: 'test-id'},
+  );
+  // Use WebSocket to block BFCache.
+  await useWebSocket(rc1_child);
+  const rc1_child_url = await rc1_child.executeScript(() => {
+    return location.href;
+  });
+  // Add a child to the iframe.
+  const rc1_grand_child = await rc1_child.addIframe();
+  const rc1_grand_child_url = await rc1_grand_child.executeScript(() => {
+    return location.href;
+  });
+
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[{'reason': "masked"}],
+      /*children=*/[{
+        'url': null,
+        'src': rc1_child_url,
+        'id': 'test-id',
+        'name': null,
+        'reasons': null,
+        'children': null
+      }]);
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-fetch.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-fetch.tentative.window.js
new file mode 100644
index 000000000000000..c8f53a660fa9a14
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-fetch.tentative.window.js
@@ -0,0 +1,40 @@
+// META: title=Ensure that ongoing fetch upon entering bfcache blocks bfcache and recorded.
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: timeout=long
+
+'use strict';
+
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+  const wavURL = new URL(get_host_info().HTTP_REMOTE_ORIGIN + '/fetch/range/resources/long-wav.py');
+  await rc1.executeScript((wavURL) => {
+    // Register pagehide handler to create a fetch request.
+    addEventListener('pagehide', (wavURL) => {
+      fetch(wavURL, {
+        keepalive: true
+      });
+    })
+  });
+
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[{'reason': 'fetch'}],
+      /*children=*/[]);
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-iframes-without-attributes.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-iframes-without-attributes.tentative.window.js
new file mode 100644
index 000000000000000..cda0ac43944742f
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-iframes-without-attributes.tentative.window.js
@@ -0,0 +1,103 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+'use strict';
+
+// Ensure that empty attributes are reported as empty strings and missing
+// attributes are reported as null.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+  // Add a cross-origin iframe.
+  const rc1_child = await rc1.addIframe(
+      /*extraConfig=*/ {
+        origin: 'HTTP_REMOTE_ORIGIN',
+        scripts: [],
+        headers: [],
+      },
+      /*attributes=*/ {id: '', name: ''},
+  );
+  const rc2_child = await rc1.addIframe(
+    /*extraConfig=*/ {
+      origin: 'HTTP_REMOTE_ORIGIN',
+      scripts: [],
+      headers: [],
+    },
+    /*attributes=*/ {},
+  );
+  const rc3_child = await rc1.addIframe(
+    /*extraConfig=*/ {},
+    /*attributes=*/ {},
+  );
+  const rc4_child = await rc1.addIframe(
+    /*extraConfig=*/ {},
+    /*attributes=*/ {id: '', name: ''},
+  );
+  // Use WebSocket to block BFCache.
+  await useWebSocket(rc1);
+  const rc1_child_url = await rc1_child.executeScript(() => {
+    return location.href;
+  });
+  const rc2_child_url = await rc2_child.executeScript(() => {
+    return location.href;
+  });
+  const rc3_child_url = await rc3_child.executeScript(() => {
+    return location.href;
+  });
+  const rc4_child_url = await rc4_child.executeScript(() => {
+    return location.href;
+  });
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[{'reason': 'websocket'}],
+      /*children=*/[{
+        'url': null,
+        'src': rc1_child_url,
+        // Id and name should be empty.
+        'id': '',
+        'name': '',
+        'reasons': null,
+        'children': null
+      }, {
+        'url': null,
+        'src': rc2_child_url,
+        // Id and name should be null.
+        'id': null,
+        'name': null,
+        'reasons': null,
+        'children': null
+      },{
+        'url': rc3_child_url,
+        'src': rc3_child_url,
+        // Id and name should be null.
+        'id': null,
+        'name': null,
+        'reasons': [],
+        'children': []
+      }, {
+        'url': rc4_child_url,
+        'src': rc4_child_url,
+        'id': '',
+        'name': '',
+        'reasons': [],
+        'children': []
+      }]);
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-lock.https.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-lock.https.tentative.window.js
new file mode 100644
index 000000000000000..46d8752f20d9674
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-lock.https.tentative.window.js
@@ -0,0 +1,32 @@
+// META: title=Ensure that if WebLock is held upon entering bfcache, it cannot enter bfcache and gets reported.
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: timeout=long
+
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+
+  // Request a WebLock.
+  let return_value = await rc1.executeScript(() => {
+    return new Promise((resolve) => {
+      navigator.locks.request('resource', () => {
+        resolve(42);
+      });
+    })
+  });
+  assert_equals(return_value, 42);
+
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredFromBFCache(rc1, ['lock']);
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-navigation-failure.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-navigation-failure.tentative.window.js
new file mode 100644
index 000000000000000..faa7649bc33c3f4
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-navigation-failure.tentative.window.js
@@ -0,0 +1,26 @@
+// META: title=Ensure that navigation failure blocks bfcache and gets recorded.
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/404.py
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: timeout=long
+
+'use strict';
+const {ORIGIN} = get_host_info();
+
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ {status: 404}, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredFromBFCache(rc1, ['response-status-not-ok']);
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-not-bfcached.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-not-bfcached.tentative.window.js
new file mode 100644
index 000000000000000..1cf1d55d90f78ab
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-not-bfcached.tentative.window.js
@@ -0,0 +1,36 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+'use strict';
+
+// Ensure that notRestoredReasons is populated when not restored.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  // Use WebSocket to block BFCache.
+  await useWebSocket(rc1);
+
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[{'reason': 'websocket'}],
+      /*children=*/ []);
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-redirect-on-history.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-redirect-on-history.tentative.window.js
new file mode 100644
index 000000000000000..7191456cc845bdd
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-redirect-on-history.tentative.window.js
@@ -0,0 +1,53 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+'use strict';
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+
+// Ensure that notRestoredReasons reset after the server redirect.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  // Use WebSocket to block BFCache.
+  await useWebSocket(rc1);
+
+  // Create a remote context with the redirected URL.
+  let rc1_redirected =
+      await rcHelper.createContext(/*extraConfig=*/ {
+        origin: 'HTTP_ORIGIN',
+        scripts: [],
+        headers: [],
+      });
+
+  const redirectUrl =
+      `${ORIGIN}/common/redirect.py?location=${encodeURIComponent(rc1_redirected.url)}`;
+  // Replace the history state.
+  await rc1.executeScript((url) => {
+    window.history.replaceState(null, '', url);
+  }, [redirectUrl]);
+
+  // Navigate away.
+  const newRemoteContextHelper = await rc1.navigateToNew();
+
+  // Go back.
+  await newRemoteContextHelper.historyBack();
+
+  const navigation_entry = await rc1_redirected.executeScript(() => {
+    return performance.getEntriesByType('navigation')[0];
+  });
+  assert_equals(
+      navigation_entry.redirectCount, 1, 'Expected redirectCount is 1.');
+  // Becauase of the redirect, notRestoredReasons is reset.
+  assert_equals(
+      navigation_entry.notRestoredReasons, null,
+      'Expected notRestoredReasons is null.');
+});
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-reload.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-reload.tentative.window.js
new file mode 100644
index 000000000000000..1a8972778d287c5
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-reload.tentative.window.js
@@ -0,0 +1,50 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+'use strict';
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+
+// Ensure that notRestoredReasons reset after the server redirect.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+  // Use WebSocket to block BFCache.
+  await useWebSocket(rc1);
+
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredReasonsEquals(
+        rc1,
+        /*url=*/ rc1_url,
+        /*src=*/ null,
+        /*id=*/ null,
+        /*name=*/ null,
+        /*reasons=*/[{'reason': 'websocket'}],
+        /*children=*/ []);
+
+  // Reload.
+  await rc1.navigate(() => {
+    location.reload();
+  }, []);
+
+  // Becauase of the reload, notRestoredReasons is reset.
+  const navigation_entry = await rc1.executeScript(() => {
+    return performance.getEntriesByType('navigation')[0];
+  });
+
+  assert_equals(
+      navigation_entry.notRestoredReasons, null,
+      'Expected notRestoredReasons is null.');
+});
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-same-origin-bfcache.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-same-origin-bfcache.tentative.window.js
new file mode 100644
index 000000000000000..89d66b070ed8c4f
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-same-origin-bfcache.tentative.window.js
@@ -0,0 +1,61 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+
+'use strict';
+
+// Ensure that same-origin subtree's reasons are exposed to notRestoredReasons.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+  // Add a same-origin iframe and use WebSocket.
+  const rc1_child = await rc1.addIframe(
+      /*extra_config=*/ {}, /*attributes=*/ {id: 'test-id'});
+  await useWebSocket(rc1_child);
+
+  const rc1_child_url = await rc1_child.executeScript(() => {
+    return location.href;
+  });
+  // Add a child to the iframe.
+  const rc1_grand_child = await rc1_child.addIframe();
+  const rc1_grand_child_url = await rc1_grand_child.executeScript(() => {
+    return location.href;
+  });
+
+  // Check the BFCache result and the reported reasons.
+  await assertBFCacheEligibility(rc1, /*shouldRestoreFromBFCache=*/ false);
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[],
+      /*children=*/[{
+        'url': rc1_child_url,
+        'src': rc1_child_url,
+        'id': 'test-id',
+        'name': '',
+        'reasons': [{'reason': 'websocket'}],
+        'children': [{
+          'url': rc1_grand_child_url,
+          'src': rc1_grand_child_url,
+          'id': '',
+          'name': '',
+          'reasons': [],
+          'children': []
+        }]
+      }]);
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-same-origin-replace.tentative.window.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-same-origin-replace.tentative.window.js
new file mode 100644
index 000000000000000..1162bfaf7600fda
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/performance-navigation-timing-same-origin-replace.tentative.window.js
@@ -0,0 +1,43 @@
+// META: title=RemoteContextHelper navigation using BFCache
+// META: script=./test-helper.js
+// META: script=/common/dispatcher/dispatcher.js
+// META: script=/common/get-host-info.sub.js
+// META: script=/common/utils.js
+// META: script=/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+// META: script=/html/browsers/browsing-the-web/remote-context-helper/resources/remote-context-helper.js
+// META: script=/websockets/constants.sub.js
+// META: timeout=long
+
+'use strict';
+
+// Ensure that notRestoredReasons are accessible after history replace.
+promise_test(async t => {
+  const rcHelper = new RemoteContextHelper();
+  // Open a window with noopener so that BFCache will work.
+  const rc1 = await rcHelper.addWindow(
+      /*config=*/ null, /*options=*/ {features: 'noopener'});
+  const rc1_url = await rc1.executeScript(() => {
+    return location.href;
+  });
+
+  // Use WebSocket to block BFCache.
+  await useWebSocket(rc1);
+  // Navigate away.
+  const newRemoteContextHelper = await rc1.navigateToNew();
+  // Replace the history state to a same-origin site.
+  await newRemoteContextHelper.executeScript((destUrl) => {
+    window.history.replaceState(null, '', '#');
+  });
+  // Go back.
+  await newRemoteContextHelper.historyBack();
+
+  // Reasons are not reset for same-origin replace.
+  await assertNotRestoredReasonsEquals(
+      rc1,
+      /*url=*/ rc1_url,
+      /*src=*/ null,
+      /*id=*/ null,
+      /*name=*/ null,
+      /*reasons=*/[{'reason': 'websocket'}],
+      /*children=*/ []);
+});
diff --git a/test/fixtures/wpt/performance-timeline/not-restored-reasons/test-helper.js b/test/fixtures/wpt/performance-timeline/not-restored-reasons/test-helper.js
new file mode 100644
index 000000000000000..ba9a4c0342fcb53
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/not-restored-reasons/test-helper.js
@@ -0,0 +1,57 @@
+// META: script=../../html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+
+async function assertNotRestoredReasonsEquals(
+    remoteContextHelper, url, src, id, name, reasons, children) {
+  let result = await remoteContextHelper.executeScript(() => {
+    return performance.getEntriesByType('navigation')[0].notRestoredReasons;
+  });
+  assertReasonsStructEquals(
+      result, url, src, id, name, reasons, children);
+}
+
+function assertReasonsStructEquals(
+    result, url, src, id, name, reasons, children) {
+  assert_equals(result.url, url);
+  assert_equals(result.src, src);
+  assert_equals(result.id, id);
+  assert_equals(result.name, name);
+
+  // Reasons should match.
+  let expected = new Set(reasons);
+  let actual = new Set(result.reasons);
+  matchReasons(extractReason(expected), extractReason(actual));
+
+  // Children should match.
+  if (children == null) {
+    assert_equals(result.children, children);
+  } else {
+    for (let j = 0; j < children.length; j++) {
+      assertReasonsStructEquals(
+          result.children[j], children[j].url,
+          children[j].src, children[j].id, children[j].name, children[j].reasons,
+          children[j].children);
+    }
+  }
+}
+
+function ReasonsInclude(reasons, targetReason) {
+  for (const reason of reasons) {
+    if (reason.reason == targetReason) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Requires:
+// - /websockets/constants.sub.js in the test file and pass the domainPort
+// constant here.
+async function useWebSocket(remoteContextHelper) {
+  let return_value = await remoteContextHelper.executeScript((domain) => {
+    return new Promise((resolve) => {
+      var webSocketInNotRestoredReasonsTests = new WebSocket(domain + '/echo');
+      webSocketInNotRestoredReasonsTests.onopen = () => { resolve(42); };
+    });
+  }, [SCHEME_DOMAIN_PORT]);
+  assert_equals(return_value, 42);
+}
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/resources/child-frame.html b/test/fixtures/wpt/performance-timeline/resources/child-frame.html
new file mode 100644
index 000000000000000..40c8f7268857d03
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/resources/child-frame.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+
+<head></head>
+<body></body>
+<script>
+  performance.mark('mark_child_frame');
+</script>
diff --git a/test/fixtures/wpt/performance-timeline/resources/empty.html b/test/fixtures/wpt/performance-timeline/resources/empty.html
new file mode 100644
index 000000000000000..e69de29bb2d1d64
diff --git a/test/fixtures/wpt/performance-timeline/resources/going-back.html b/test/fixtures/wpt/performance-timeline/resources/going-back.html
new file mode 100644
index 000000000000000..f4a26669baa1630
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/resources/going-back.html
@@ -0,0 +1,9 @@
+<!doctype html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+onload = (event) => {
+  history.back();
+};
+</script>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/resources/include-frames-helper.js b/test/fixtures/wpt/performance-timeline/resources/include-frames-helper.js
new file mode 100644
index 000000000000000..a56489baaf4d06d
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/resources/include-frames-helper.js
@@ -0,0 +1,60 @@
+const verifyEntries = (entries, filterOptions) => {
+  for (const filterOption of filterOptions) {
+    let countBeforeFiltering = entries.length;
+
+    // Using negate of the condition so that the next filtering is applied on less entries.
+    entries = entries.filter(
+      e => !(e.entryType == filterOption['entryType'] && e.name.includes(filterOption['name'])));
+
+    assert_equals(
+      countBeforeFiltering - entries.length, filterOption['expectedCount'], filterOption['failureMsg']);
+  }
+}
+
+const createFilterOption = (name, entryType, expectedCount, msgPrefix, description = '') => {
+  if (description) {
+    description = ' ' + description;
+  }
+
+  let failureMsg =
+    `${msgPrefix} should have ${expectedCount} ${entryType} entries for name ${name}` + description;
+
+  return {
+    name: name,
+    entryType: entryType,
+    expectedCount: expectedCount,
+    failureMsg: failureMsg
+  };
+}
+
+const loadChildFrame = (src) => {
+  return new Promise(resolve => {
+
+    const childFrame = document.createElement('iframe');
+
+    childFrame.addEventListener("load", resolve);
+
+    childFrame.src = src;
+
+    document.body.appendChild(childFrame);
+  });
+}
+
+const loadChildFrameAndGrandchildFrame = (src) => {
+  return new Promise(resolve => {
+
+    const crossOriginChildFrame = document.createElement('iframe');
+
+    // Wait for the child frame to send a message. The child frame would send a message
+    // when it loads its child frame.
+    window.addEventListener('message', e => {
+      if (e.data == 'Load completed') {
+        resolve();
+      }
+    });
+
+    crossOriginChildFrame.src = src;
+
+    document.body.appendChild(crossOriginChildFrame)
+  });
+}
diff --git a/test/fixtures/wpt/performance-timeline/resources/include-frames-subframe.html b/test/fixtures/wpt/performance-timeline/resources/include-frames-subframe.html
new file mode 100644
index 000000000000000..0d43f418a096a04
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/resources/include-frames-subframe.html
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+
+<head>
+</head>
+<!--
+  This html is embedded as a sub-frame in include-frames-originA-B-A.html,
+  include-frames-originA-B-B.html and include-frames-originA-A-A.html. Once embedded,
+  this would take a url parameter named origin which is the origin of the child frame
+  this html is to load in step 3 listed below.
+  It does,
+  1, waits for load.
+  2, creates a single mark performance entry.
+  3, creates and loads a child frame, and waits for it to load.
+  4. verify entries obtained from this frame.
+-->
+
+<body>
+  <script>
+    (async () => {
+      // Wait for load.
+      await new Promise(resolve => window.addEventListener("load", resolve));
+
+      // Mark.
+      performance.mark("mark_subframe");
+
+      // Create and load an iframe and wait for load.
+      await new Promise(resolve => {
+        const childFrame = document.createElement('iframe');
+
+        childFrame.addEventListener('load', async () => {
+          window.parent.postMessage('Load completed', "*");
+          resolve();
+        });
+
+        childFrame.src = (new URL(document.location)).searchParams.get('origin')
+          + '/performance-timeline/resources/child-frame.html';
+
+        document.body.appendChild(childFrame);
+      }
+      );
+    })();
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/resources/json_resource.json b/test/fixtures/wpt/performance-timeline/resources/json_resource.json
new file mode 100644
index 000000000000000..68b6ac1d56f7c25
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/resources/json_resource.json
@@ -0,0 +1,4 @@
+{
+  "name": "nav_id_test",
+  "target": "resource_timing"
+}
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/resources/make_long_task.js b/test/fixtures/wpt/performance-timeline/resources/make_long_task.js
new file mode 100644
index 000000000000000..a52d6d839298ccb
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/resources/make_long_task.js
@@ -0,0 +1,4 @@
+(function () {
+  let now = window.performance.now();
+  while (window.performance.now() < now + 60);
+}());
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/resources/navigation-id-detached-frame-page.html b/test/fixtures/wpt/performance-timeline/resources/navigation-id-detached-frame-page.html
new file mode 100644
index 000000000000000..02aafbb5c78368c
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/resources/navigation-id-detached-frame-page.html
@@ -0,0 +1,21 @@
+<!DOCTYPE HTML>
+<html>
+
+<head>
+  <meta charset="utf-8">
+  <title>The navigation_id Detached iframe Page.</title>
+</head>
+
+<body>
+  <script>
+      window.addEventListener("load", () => {
+        setTimeout(() => {
+          const container = window.frameElement;
+          container.remove();
+        }, 10);
+        performance.mark('mark-window-detached-frame');
+      });
+  </script>
+</body>
+
+</html>
\ No newline at end of file
diff --git a/test/fixtures/wpt/performance-timeline/resources/worker-navigation-id.js b/test/fixtures/wpt/performance-timeline/resources/worker-navigation-id.js
new file mode 100644
index 000000000000000..3a2740d0675c84f
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/resources/worker-navigation-id.js
@@ -0,0 +1,6 @@
+self.onmessage = () => {
+  const mark_name = 'user_timig_mark';
+  performance.mark(mark_name);
+  postMessage(performance.getEntriesByName(mark_name)[0].navigationId);
+  self.close();
+}
diff --git a/test/fixtures/wpt/performance-timeline/supportedEntryTypes-cross-realm-access.html b/test/fixtures/wpt/performance-timeline/supportedEntryTypes-cross-realm-access.html
new file mode 100644
index 000000000000000..8b86a6398bfd499
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/supportedEntryTypes-cross-realm-access.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Cross-realm access of supportedEntryTypes returns Array of another realm</title>
+<link rel="help" href="https://w3c.github.io/performance-timeline/#supportedentrytypes-attribute">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<body>
+<script>
+test(t => {
+  const iframe = document.createElement("iframe");
+  t.add_cleanup(() => { iframe.remove(); });
+  iframe.onload = t.step_func_done(() => {
+    const otherWindow = iframe.contentWindow;
+    assert_true(otherWindow.PerformanceObserver.supportedEntryTypes instanceof otherWindow.Array);
+  });
+  document.body.append(iframe);
+});
+</script>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/detached-frame.html b/test/fixtures/wpt/performance-timeline/tentative/detached-frame.html
new file mode 100644
index 000000000000000..70019223a648d95
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/detached-frame.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<head>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+</body>
+<script>
+promise_test(async () => {
+  performance.clearResourceTimings()
+
+  // Create child iframe.
+  const childFrame = document.createElement('iframe')
+  childFrame.src = "../resources/child-frame.html"
+  document.body.appendChild(childFrame)
+
+  // wait until the child frame's onload event fired
+  await new Promise(r => childFrame.addEventListener("load", r));
+
+  const childWindow = childFrame.contentWindow;
+  // Detach the child frame
+  document.body.removeChild(childFrame);
+
+  const entries = childWindow.performance.getEntries({ includeChildFrames: true });
+  const parent_entries = performance.getEntries({ includeChildFrames: true });
+}, "GetEntries of a detached parent frame does not crash");
+</script>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-A-A.html b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-A-A.html
new file mode 100644
index 000000000000000..57623e5b33bfb00
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-A-A.html
@@ -0,0 +1,93 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src=/common/get-host-info.sub.js></script>
+  <script src="../resources/include-frames-helper.js"></script>
+</head>
+
+<body>
+  <script>
+    const verifyMainFrameEntries = (entries, description = '') => {
+      let filterOptions = [
+        createFilterOption('include-frames-originA-A-A', 'navigation', 1, 'Main Frame', description),
+        createFilterOption('include-frames-subframe', 'resource', 1, 'Main Frame', description),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyChildFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('include-frames-subframe', 'navigation', 1, 'Child Frame'),
+        createFilterOption('child-frame.html', 'resource', 1, 'Child Frame'),
+        createFilterOption('mark_subframe', 'mark', 1, 'Child frame')
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyGrandchildFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('child-frame.html', 'navigation', 1, 'Grandchild Frame'),
+        createFilterOption('mark_child_frame', 'mark', 1, 'Grandchild frame')
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    promise_test(async () => {
+      performance.clearResourceTimings();
+
+      // Load a child frame. The child frame upon loading would load a child frame of its own.
+      await loadChildFrameAndGrandchildFrame(
+        '../resources/include-frames-subframe.html?origin=' + get_host_info().ORIGIN);
+
+      // Verify entries retrieved from main frame.
+      const entries = performance.getEntries({ includeChildFrames: true });
+
+      verifyMainFrameEntries(entries);
+
+      verifyChildFrameEntries(entries);
+
+      verifyGrandchildFrameEntries(entries);
+
+      // 1 entry for parent, 1 for child, 1 for grandchild.
+      const navigationEntries = performance.getEntries({ entryType: "navigation", includeChildFrames: true });
+      assert_equals(navigationEntries.length, 3, 'Navigation entries should be 3.');
+
+      const markedChildFrameEntries = performance.getEntries(
+        { name: 'mark_subframe', includeChildFrames: true });
+      assert_equals(markedChildFrameEntries.length, 1, 'Child frame mark entries should be 1.');
+
+      const markedGrandchildFrameEntries = performance.getEntries(
+        { name: 'mark_child_frame', includeChildFrames: true });
+      assert_equals(markedGrandchildFrameEntries.length, 1, 'Grand child frame mark entries should be 1.');
+
+      // Test cases where includeChildFrames is false.
+      const entriesWithNoFitlerOptions = performance.getEntries();
+
+      const entriesWithoutIncludingChildFrames = performance.getEntries({ includeChildFrames: false });
+
+      const navigationEntriesWithoutIncludingChildFrames = performance.getEntries({ entryType: "navigation", includeChildFrames: false });
+
+      const markedEntriesWithoutIncludingChildFrames = performance.getEntries(
+        { name: 'entry-name', includeChildFrames: false });
+
+      verifyMainFrameEntries(entriesWithNoFitlerOptions, 'with no filter options.');
+
+      verifyMainFrameEntries(entriesWithoutIncludingChildFrames, 'with includingChildFrames being false.')
+
+      // 1 entry for main frame.
+      assert_equals(navigationEntriesWithoutIncludingChildFrames.length, 1,
+        'Navigation entries with includeChildFrame being false should be 1.');
+
+      // 0 entry since grandchild frame is not included.
+      assert_equals(markedEntriesWithoutIncludingChildFrames.length, 0,
+        'Mark entries with includeChildFrame being false should be 0.');
+
+    }, 'GetEntries of a document of origin A, its child frame of origin B and \
+    its grandchild frame of origin A.');
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-A.html b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-A.html
new file mode 100644
index 000000000000000..bcb9a81657f227b
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-A.html
@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="../resources/include-frames-helper.js"></script>
+</head>
+
+<body>
+  <script>
+    const verifyMainFrameEntries = (entries, description = '') => {
+      let filterOptions = [
+        createFilterOption('include-frames-originA-A', 'navigation', 1, 'Main Frame', description),
+        createFilterOption('child-frame.html', 'resource', 1, 'Main Frame', description),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyChildFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('child-frame.html', 'navigation', 1, 'Child Frame'),
+        createFilterOption('mark_child_frame', 'mark', 1, 'Child Frame'),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    promise_test(async () => {
+      performance.clearResourceTimings();
+
+      // Load a child frame.
+      await loadChildFrame('../resources/child-frame.html');
+
+      const entries = performance.getEntries({ includeChildFrames: true });
+
+      const navigationEntries = performance.getEntries({ entryType: "navigation", includeChildFrames: true });
+
+      const markedEntries = performance.getEntries(
+        { name: 'mark_child_frame', includeChildFrames: true });
+
+      verifyMainFrameEntries(entries);
+
+      verifyChildFrameEntries(entries);
+
+      // 1 entry for main frame, 1 for child frame.
+      assert_equals(navigationEntries.length, 2, 'Navigation entries should be 2.');
+
+      // 1 entry for child frame.
+      assert_equals(markedEntries.length, 1, 'Mark entries should be 1.');
+
+      // Test cases where includeChildFrames is false.
+      const entriesWithNoFitlerOptions = performance.getEntries();
+
+      const entriesWithoutIncludingChildFrames = performance.getEntries({ includeChildFrames: false });
+
+      const navigationEntriesWithoutIncludingChildFrames = performance.getEntries({ entryType: "navigation", includeChildFrames: false });
+
+      const markedEntriesWithoutIncludingChildFrames = performance.getEntries(
+        { name: 'mark_child_frame', includeChildFrames: false });
+
+      verifyMainFrameEntries(entriesWithNoFitlerOptions, 'with no filter options.');
+
+      verifyMainFrameEntries(entriesWithoutIncludingChildFrames, 'with includeChildFrame being false.');
+
+      // 1 entry for main frame.
+      assert_equals(navigationEntriesWithoutIncludingChildFrames.length, 1,
+        'Navigation entries with includeChildFrame being false should be 1.');
+
+      // 0 entry for child frame.
+      assert_equals(markedEntriesWithoutIncludingChildFrames.length, 0,
+        'Mark entries with includeChildFrame being false should be 0.');
+
+    }, 'GetEntries of a document of origin A and its child frame of origin A.');
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-AA.html b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-AA.html
new file mode 100644
index 000000000000000..cccbf4100dd2aec
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-AA.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="../resources/include-frames-helper.js"></script>
+</head>
+
+<body>
+  <script>
+    const verifyMainFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('include-frames-originA-AA', 'navigation', 1, 'Main Frame'),
+        createFilterOption('child-frame.html', 'navigation', 2, 'Child Frames'),
+        createFilterOption('child-frame.html', 'resource', 2, 'Main Frame'),
+        createFilterOption('mark_child_frame', 'mark', 2, 'Child frames')
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyPerformanceEntries = () => {
+      const entries = performance.getEntries({ includeChildFrames: true });
+
+      const navigationEntries = performance.getEntries({ entryType: "navigation", includeChildFrames: true });
+
+      const markedEntries = performance.getEntries(
+        { name: 'mark_child_frame', includeChildFrames: true });
+
+      verifyMainFrameEntries(entries);
+
+      // 1 entry for main frame, 1 for each child frame.
+      assert_equals(navigationEntries.length, 3, 'Navigation entries should be 3.');
+
+      // 1 entry for each child frame.
+      assert_equals(markedEntries.length, 2, 'Mark entries should be 2.');
+    }
+
+    promise_test(async () => {
+      performance.clearResourceTimings();
+
+      // Load first child iframe.
+      const promise1 = loadChildFrame('../resources/child-frame.html');
+
+      // Load second child iframe.
+      const promise2 = loadChildFrame('../resources/child-frame.html');
+
+      return Promise.all([promise1, promise2]).then(verifyPerformanceEntries);
+    }, 'GetEntries of a document of origin A and its two child frames both of origin A.');
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-AB.html b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-AB.html
new file mode 100644
index 000000000000000..d630665b652cb13
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-AB.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src=/common/get-host-info.sub.js></script>
+  <script src="../resources/include-frames-helper.js"></script>
+</head>
+
+<body>
+  <script>
+    const verifyMainFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('include-frames-originA-AB', 'navigation', 1, 'Main Frame'),
+        createFilterOption('child-frame.html', 'navigation', 1, 'Child Frames'),
+        createFilterOption('child-frame.html', 'resource', 2, 'Main Frame'),
+        createFilterOption('mark_child_frame', 'mark', 1, 'Child frames')
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyPerformanceEntries = () => {
+      const entries = performance.getEntries({ includeChildFrames: true });
+
+      const navigationEntries = performance.getEntries({ entryType: "navigation", includeChildFrames: true });
+
+      const markedEntries = performance.getEntries(
+        { name: 'mark_child_frame', includeChildFrames: true });
+
+      verifyMainFrameEntries(entries);
+
+      // 1 entry for main frame, 1 for local child frame.
+      assert_equals(navigationEntries.length, 2, 'Navigation entries should be 2.');
+
+      // 1 entry for local child frame.
+      assert_equals(markedEntries.length, 1, 'Mark entries should be 1.');
+    }
+
+    promise_test(() => {
+      performance.clearResourceTimings();
+
+      // Load first child iframe.
+      sameOriginPromise = loadChildFrame('../resources/child-frame.html');
+
+      // Create second child iframe.
+      crossOriginPromise = loadChildFrame(
+        get_host_info().HTTP_REMOTE_ORIGIN + '/resources/child-frame.html');
+
+      return Promise.all([sameOriginPromise, crossOriginPromise]).then(verifyPerformanceEntries);
+    }, 'GetEntries of a document of origin A and its two child frames of origin A and B respectively.');
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B-A.html b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B-A.html
new file mode 100644
index 000000000000000..58cad40faba658f
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B-A.html
@@ -0,0 +1,91 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src=/common/get-host-info.sub.js></script>
+  <script src="../resources/include-frames-helper.js"></script>
+</head>
+
+<body>
+  <script>
+    const verifyMainFrameEntries = (entries, description = '') => {
+      let filterOptions = [
+        createFilterOption('include-frames-originA-B-A', 'navigation', 1, 'Main Frame', description),
+        createFilterOption('include-frames-subframe', 'resource', 1, 'Main Frame', description),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyChildFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('include-frames-subframe', 'navigation', 0, 'Child Frame'),
+        createFilterOption('child-frame.html', 'resource', 0, 'Child Frame'),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyGrandchildFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('child-frame.html', 'navigation', 1, 'Grandchild Frame'),
+        createFilterOption('mark_child_frame', 'mark', 1, 'Grandchild frame')
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    promise_test(async () => {
+
+      performance.clearResourceTimings();
+
+      // Load a child frame. The child frame upon loading would load a child frame of its own.
+      await loadChildFrameAndGrandchildFrame(get_host_info().REMOTE_ORIGIN +
+        '/performance-timeline/resources/include-frames-subframe.html?origin=' + get_host_info().ORIGIN);
+
+      const entries = performance.getEntries({ includeChildFrames: true });
+
+      const navigationEntries = performance.getEntries({ entryType: "navigation", includeChildFrames: true });
+
+      const markedEntries = performance.getEntries(
+        { name: 'mark_child_frame', includeChildFrames: true });
+
+      verifyMainFrameEntries(entries);
+
+      verifyChildFrameEntries(entries);
+
+      verifyGrandchildFrameEntries(entries);
+
+      // 1 entry for main frame, 1 for grandchild frame.
+      assert_equals(navigationEntries.length, 2, 'Navigation entries should be 2.');
+
+      // 1 entry for grandchild frame.
+      assert_equals(markedEntries.length, 1, 'Mark entries should be 1.');
+
+      // Test cases where includeChildFrames is false.
+      const entriesWithNoFitlerOptions = performance.getEntries();
+
+      const entriesWithoutIncludingChildFrames = performance.getEntries({ includeChildFrames: false });
+
+      const navigationEntriesWithoutIncludingChildFrames = performance.getEntries({ entryType: "navigation", includeChildFrames: false });
+
+      const markedEntriesWithoutIncludingChildFrames = performance.getEntries(
+        { name: 'mark_child_frame', includeChildFrames: false });
+
+      verifyMainFrameEntries(entriesWithNoFitlerOptions, 'with no filter options.');
+
+      verifyMainFrameEntries(entriesWithoutIncludingChildFrames, 'with includeChildFrame being false.');
+
+      // 1 entry for main frame.
+      assert_equals(navigationEntriesWithoutIncludingChildFrames.length, 1,
+        'Navigation entries with includeChildFrame being false should be 1.');
+
+      // 0 entry since grandchild frame is not included.
+      assert_equals(markedEntriesWithoutIncludingChildFrames.length, 0,
+        'Mark entries with includeChildFrame being false should be 0.');
+
+    }, 'GetEntries of a document of origin A, its child frame of origin B and \
+    its grandchild frame of origin A.');
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B-B.html b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B-B.html
new file mode 100644
index 000000000000000..2368a8e881aa3a3
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B-B.html
@@ -0,0 +1,57 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src=/common/get-host-info.sub.js></script>
+  <script src="../resources/include-frames-helper.js"></script>
+</head>
+
+<body>
+  <script>
+    const verifyMainFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('include-frames-originA-B-B', 'navigation', 1, 'Main Frame'),
+        createFilterOption('include-frames-subframe', 'resource', 1, 'Main Frame'),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyChildFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('include-frames-subframe', 'navigation', 0, 'Child Frame'),
+        createFilterOption('child-frame.html', 'resource', 0, 'Child Frame'),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyGrandchildFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('child-frame.html', 'navigation', 0, 'Grandchild Frame'),
+        createFilterOption('mark_child_frame', 'mark', 0, 'Grandchild frame')
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    promise_test(async () => {
+      performance.clearResourceTimings();
+
+      // Load a origin child frame. The child frame upon loading would load a child frame of its own.
+      await loadChildFrameAndGrandchildFrame(get_host_info().REMOTE_ORIGIN
+        + '/performance-timeline/resources/include-frames-subframe.html?origin='
+        + get_host_info().REMOTE_ORIGIN);
+
+      const entries = performance.getEntries({ includeChildFrames: true });
+
+      verifyMainFrameEntries(entries);
+
+      verifyChildFrameEntries(entries);
+
+      verifyGrandchildFrameEntries(entries);
+    }, 'GetEntries of a document of origin A, its child frame of origin B and \
+    its grandchild frame of origin B.');
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B.html b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B.html
new file mode 100644
index 000000000000000..b823d6edaa32620
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/include-frames-originA-B.html
@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src=/common/get-host-info.sub.js></script>
+  <script src="../resources/include-frames-helper.js"></script>
+</head>
+
+<body>
+  <script>
+    const verifyMainFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('include-frames-originA-B', 'navigation', 1, 'Main Frame'),
+        createFilterOption('child-frame.html', 'resource', 1, 'Main Frame'),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    const verifyChildFrameEntries = (entries) => {
+      let filterOptions = [
+        createFilterOption('child-frame.html', 'navigation', 0, 'Child Frame'),
+        createFilterOption('mark_child_frame', 'mark', 0, 'Child Frame'),
+      ];
+
+      verifyEntries(entries, filterOptions);
+    }
+
+    promise_test(async () => {
+      performance.clearResourceTimings();
+
+      await loadChildFrame(
+        get_host_info().HTTP_REMOTE_ORIGIN + '/performance_timeline/resources/child-frame.html');
+
+      const entries = performance.getEntries({ includeChildFrames: true });
+
+      const navigationEntries = performance.getEntries({ entryType: "navigation", includeChildFrames: true });
+
+      const markedEntries = performance.getEntries(
+        { name: 'mark_subframe', includeChildFrames: true });
+
+      // 1 entry for main frame.
+      assert_equals(navigationEntries.length, 1, 'Navigation entries should 1.');
+
+      // 0 entry since child frame is cross origin.
+      assert_equals(markedEntries.length, 0, 'Mark entries should 0.');
+    }, 'GetEntries of a parent Frame of origin A and its child frame of origin B');
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/performance-entry-source.html b/test/fixtures/wpt/performance-timeline/tentative/performance-entry-source.html
new file mode 100644
index 000000000000000..d10d3c5ed512b79
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/performance-entry-source.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+</head>
+
+<body>
+</body>
+<script>
+  promise_test(() => {
+    return new Promise(resolve => {
+      const navigationEntries = performance.getEntries({ type: 'navigation' })
+      const parentEntry = navigationEntries[0]
+
+      // Parent NavigationTiming source is current window.
+      assert_equals(parentEntry.source, window)
+
+      // Create child iframe.
+      const childFrame = document.createElement('iframe')
+      childFrame.src = "../resources/child-frame.html"
+      document.body.appendChild(childFrame)
+
+      childFrame.addEventListener('load', () => {
+        const markedEntries = performance.getEntries(
+          { name: 'mark_child_frame', includeChildFrames: true });
+
+        const childEntry = markedEntries[0]
+
+        // Child PerformanceMark source is the child's Window.
+        assert_equals(childEntry.source, childFrame.contentWindow)
+
+        resolve()
+      })
+    })
+  }, "PerformanceEntry source is equal to its respective Window")
+</script>
diff --git a/test/fixtures/wpt/performance-timeline/tentative/with-filter-options-originA.html b/test/fixtures/wpt/performance-timeline/tentative/with-filter-options-originA.html
new file mode 100644
index 000000000000000..6c6643df75cf09e
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/tentative/with-filter-options-originA.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+</head>
+
+<body>
+  <script>
+    promise_test(async () => {
+      performance.clearResourceTimings();
+
+      performance.mark('entry-name');
+
+      const navigationEntries = performance.getEntries({ entryType: 'navigation' });
+
+      const markedEntries = performance.getEntries(
+        { name: 'entry-name', entryType: 'mark' });
+
+      assert_equals(navigationEntries.length, 1, 'navigationEntries should be 1.');
+
+      assert_equals(markedEntries.length, 1, 'markedEntries should be 1.');
+
+    }, 'GetEntries with filter options.');
+  </script>
+</body>
diff --git a/test/fixtures/wpt/performance-timeline/timing-removed-iframe.html b/test/fixtures/wpt/performance-timeline/timing-removed-iframe.html
new file mode 100644
index 000000000000000..43988b21fbbe022
--- /dev/null
+++ b/test/fixtures/wpt/performance-timeline/timing-removed-iframe.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<head>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+test(() => {
+  const iframe = document.createElement('iframe');
+  iframe.src = "resources/empty.html"
+  document.body.appendChild(iframe);
+  const iframePerformance = iframe.contentWindow.performance;
+  iframe.parentNode.removeChild(iframe);
+  const timing = iframePerformance.timing;
+}, "Test that a removed iframe which timing is accessed does not crash the renderer.");
+</script>
diff --git a/test/fixtures/wpt/resource-timing/META.yml b/test/fixtures/wpt/resource-timing/META.yml
index 662c42cb664219d..153654eae8b1a1b 100644
--- a/test/fixtures/wpt/resource-timing/META.yml
+++ b/test/fixtures/wpt/resource-timing/META.yml
@@ -1,6 +1,5 @@
 spec: https://w3c.github.io/resource-timing/
 suggested_reviewers:
   - plehegar
-  - zqzhang
   - igrigorik
   - yoavweiss
diff --git a/test/fixtures/wpt/resource-timing/body-size-cross-origin.https.html b/test/fixtures/wpt/resource-timing/body-size-cross-origin.https.html
new file mode 100644
index 000000000000000..b0340139bf7f402
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/body-size-cross-origin.https.html
@@ -0,0 +1,63 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Verify that encodedBodySize/decodedBodySize are CORS-protected rather than TAO-protected</title>
+<link rel="author" title="Noam Rosenthal" href="nrosenthal@chromium.org">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="/common/utils.js"></script>
+</head>
+<body>
+<script>
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+
+async function test_body_size({mode, tao, expected_body_sizes}) {
+    promise_test(async t => {
+        const origin = mode === "same-origin" ? ORIGIN : REMOTE_ORIGIN;
+        const url = new URL(`${origin}/images/red.png?uid=${token()}`,
+                            location.href);
+        const pipes = [];
+        if (mode === "cors")
+            pipes.push("header(Access-Control-Allow-Origin,*)");
+        if (tao)
+            pipes.push("header(Timing-Allow-Origin,*)");
+        const img = document.createElement("img");
+        if (mode === "cors")
+            img.crossOrigin = "anonymous";
+
+        if (pipes.length)
+            url.searchParams.set("pipe", pipes.join("|"));
+        img.src = url.toString();
+        await img.decode();
+        const [entry] = performance.getEntriesByName(url.toString());
+        if (expected_body_sizes) {
+            assert_greater_than(entry.encodedBodySize, 0);
+            assert_greater_than(entry.decodedBodySize, 0);
+        } else {
+            assert_equals(entry.encodedBodySize, 0);
+            assert_equals(entry.decodedBodySize, 0);
+        }
+
+        if (tao || mode === "same-origin")
+          assert_equals(entry.transferSize, entry.encodedBodySize + 300);
+        else
+          assert_equals(entry.transferSize, 0);
+
+    }, `Retrieving a ${mode} resource ${
+        tao ? "with" : "without"} Timing-Allow-Origin should ${
+        expected_body_sizes ? "expose" : "not expose"
+        } body size`);
+}
+
+test_body_size({mode: "same-origin", tao: false, expected_body_sizes: true});
+test_body_size({mode: "same-origin", tao: true, expected_body_sizes: true});
+test_body_size({mode: "no-cors", tao: false, expected_body_sizes: false});
+test_body_size({mode: "no-cors", tao: true, expected_body_sizes: false});
+test_body_size({mode: "cors", tao: false, expected_body_sizes: true});
+test_body_size({mode: "cors", tao: true, expected_body_sizes: true});
+
+</script>
+</body>
+</html>
diff --git a/test/fixtures/wpt/resource-timing/content-type-parsing.html b/test/fixtures/wpt/resource-timing/content-type-parsing.html
new file mode 100644
index 000000000000000..c0081eb4137d9f3
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/content-type-parsing.html
@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the parsing of content-type of resources.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+
+// Utility function picked from https://github.com/web-platform-tests/wpt/blob/master/mimesniff/mime-types/charset-parameter.window.js
+function isByteCompatible(str) {
+  // see https://fetch.spec.whatwg.org/#concept-header-value-normalize
+  if(/^[\u0009\u0020\u000A\u000D]+|[\u0009\u0020\u000A\u000D]+$/.test(str)) {
+    return "header-value-incompatible";
+  }
+
+  for(let i = 0; i < str.length; i++) {
+    const charCode = str.charCodeAt(i);
+    // See https://fetch.spec.whatwg.org/#concept-header-value
+    if(charCode > 0xFF) {
+      return "incompatible";
+    } else if(charCode === 0x00 || charCode === 0x0A || charCode === 0x0D) {
+      return "header-value-incompatible";
+    }
+  }
+  return "compatible";
+}
+
+// Test for content-type parsing.
+const run_content_type_parsing_tests = (json_entries) => {
+  json_entries.forEach( (json_entry, i) => {
+    promise_test(async t => {
+        let url = "/fetch/content-type/resources/content-type.py?single_header&";
+        json_entry.contentType.forEach(val => {
+          url += "value=" + encodeURIComponent(val) + "&";
+        });
+        fetch(url);
+        const entry = await new Promise(resolve => new PerformanceObserver((entryList, observer) => {
+            observer.disconnect();
+            resolve(entryList.getEntries()[0]);
+        }).observe({entryTypes: ['resource']}));
+        assert_equals(entry.contentType, json_entry["mimeType"]);
+    }, "content-type " + i + " : " + json_entry.contentType);
+  });
+}
+
+// Test for mime-type parsing.
+const run_mime_type_parsing_tests = (json_entries) => {
+  json_entries.forEach( (val, i) => {
+    if(typeof val === "string" || val.navigable === undefined || isByteCompatible(val.input) !== "compatible") {
+      return;
+    }
+    const output = val.output === null ? "" : val.output
+    promise_test(async t => {
+        let url = `/fetch/content-type/resources/content-type.py?single_header&value=${val.input}`;
+        fetch(url);
+        const entry = await new Promise(resolve => new PerformanceObserver((entryList, observer) => {
+            observer.disconnect();
+            resolve(entryList.getEntries()[0]);
+        }).observe({entryTypes: ['resource']}));
+        assert_equals(entry.contentType, output);
+    }, "mime-type " + i + " : " + val.input);
+  });
+}
+
+Promise.all([
+    fetch("/fetch/content-type/resources/content-types.json"),
+    fetch("/mimesniff/mime-types/resources/mime-types.json")
+  ]).then(([res, res2]) => res.json().then(run_content_type_parsing_tests)
+    .then(() => res2.json().then(run_mime_type_parsing_tests)));
+
+</script>
+</body>
+</html>
\ No newline at end of file
diff --git a/test/fixtures/wpt/resource-timing/content-type.html b/test/fixtures/wpt/resource-timing/content-type.html
new file mode 100644
index 000000000000000..5a09a9114f2c28b
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/content-type.html
@@ -0,0 +1,127 @@
+<!DOCTYPE html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the content-type of resources.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+</head>
+<body>
+<script>
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+const SAME_ORIGIN = location.origin;
+
+
+// Content-type for same origin resources is exposed.
+const run_test = (loader, contentType) => {
+  let path = `/resource-timing/resources/content-type.py?content_type=${contentType}`;
+  const url = new URL(path, ORIGIN);
+  attribute_test(
+    loader, url,
+    entry => {
+        assert_equals(entry.contentType, contentType,
+            `content-type for ${entry.name} should be ${contentType}`);
+    });
+}
+
+// Content-type is empty string when a no-cors request is made for cross
+// origin resource.
+// Content-type is empty for cross origin iframes.
+const run_test_cross_origin = (loader, contentType) => {
+  let path = `/resource-timing/resources/content-type.py?content_type=${contentType}`;
+  const url = new URL(path, REMOTE_ORIGIN);
+  attribute_test(
+    loader, url,
+    entry => {
+        assert_equals(entry.contentType, "",
+            `content-type for ${entry.name} should be ""`);
+    });
+}
+
+const resource_loaders_and_types = [
+  [load.font, ["font/woff", "font/otf"]],
+  [load.image, ["image/png", "image/jpg"]],
+  [load.script, ["application/javascript", "text/javascript"]],
+  [load.stylesheet, ["text/css"]],
+  [load.xhr_async, ["application/x-gzip", "application/pdf"]],
+  [load.iframe, ["text/html"]]
+];
+
+resource_loaders_and_types.forEach(resource => {
+  let loader = resource[0];
+  let content_types = resource[1];
+  content_types.forEach(type => {
+    run_test(loader, type);
+    run_test_cross_origin(loader, type);
+  })
+});
+
+
+// Content-type is exposed for cors request for cross-origin resources.
+const run_test_cross_origin_allow_origin = (loader_with_attr,contentType) => {
+  let path = `/resource-timing/resources/content-type.py?content_type=${contentType}&allow_origin=${ORIGIN}`;
+  const url = new URL(path, REMOTE_ORIGIN);
+  loader_with_crossOrigin_attr = async url => {
+    return loader_with_attr(url, {"crossOrigin": "anonymous"});
+  }
+  attribute_test(
+    loader_with_crossOrigin_attr, url,
+    entry => {
+        assert_equals(entry.contentType, contentType,
+            `content-type for ${entry.name} should be ${contentType}`);
+    });
+}
+
+const resource_loaders_with_attrs_and_types = [
+  [load.image_with_attrs, ["image/gif", "image/jpeg"]],
+  [load.script_with_attrs, ["application/javascript", "text/javascript"]],
+  [load.stylesheet_with_attrs, ["text/css"]],
+]
+
+resource_loaders_with_attrs_and_types.forEach(resource => {
+  let loader = resource[0];
+  let content_types = resource[1];
+  content_types.forEach(type => {
+    run_test_cross_origin_allow_origin(loader, type);
+  })
+});
+
+// Content-type for iframes is empty when cross origin redirects are present.
+var destUrl = `${SAME_ORIGIN}/resource-timing/resources/multi_redirect.py?`;
+destUrl += `page_origin=${SAME_ORIGIN}`;
+destUrl += `&cross_origin=${REMOTE_ORIGIN}`;
+destUrl += `&final_resource=/resource-timing/resources/content-type.py?content_type=text/html`;
+attribute_test(
+    load.iframe, new URL(destUrl),
+    entry => {
+        assert_equals(entry.contentType, "",
+            `content-type should be empty for iframes having cross origin redirects`);
+});
+
+
+// Content-type for iframes is exposed for same origin redirects.
+var destUrl = `${SAME_ORIGIN}/resource-timing/resources/redirect-cors.py`;
+destUrl += `?location=${SAME_ORIGIN}/resource-timing/resources/content-type.py?content_type=text/html`;
+attribute_test(
+    load.iframe, new URL(destUrl),
+    entry => {
+        assert_equals(entry.contentType, "text/html",
+            `content-type should be exposed for iframes having only same origin redirects`);
+});
+
+// Content-type for iframes is not exposed if any redirect is not same origin.
+var finalDestUrl = `${SAME_ORIGIN}/resource-timing/resources/content-type.py?content_type=text/html`;
+var interimDestUrl = `${REMOTE_ORIGIN}/resource-timing/resources/resources/redirect-cors.py?location=` + encodeURIComponent(finalDestUrl);
+var destUrl = `${SAME_ORIGIN}/resource-timing/resources/redirect-cors.py?location=` + encodeURIComponent(interimDestUrl);
+attribute_test(
+    load.iframe, new URL(destUrl),
+    entry => {
+        assert_equals(entry.contentType, "",
+            `content-type should not be exposed for iframes with any non-same-origin redirect`);
+});
+</script>
+</body>
+</html>
diff --git a/test/fixtures/wpt/resource-timing/cross-origin-start-end-time-with-redirects.html b/test/fixtures/wpt/resource-timing/cross-origin-start-end-time-with-redirects.html
index 1b107d3aef7764d..8e368d138077457 100644
--- a/test/fixtures/wpt/resource-timing/cross-origin-start-end-time-with-redirects.html
+++ b/test/fixtures/wpt/resource-timing/cross-origin-start-end-time-with-redirects.html
@@ -19,13 +19,19 @@
 const blank_page = `/resource-timing/resources/blank_page_green.htm`;
 const destUrl = `/common/slow-redirect.py?delay=${delay}&location=${REMOTE_ORIGIN}/${blank_page}`;
 
-const timeBefore = performance.now()
-attribute_test(load.iframe, destUrl, entry => {
-    assert_equals(entry.startTime, entry.fetchStart, 'startTime and fetchStart should be equal');
-    assert_greater_than(entry.startTime, timeBefore, 'startTime and fetchStart should be greater than the time before fetching');
-    // See https://github.com/w3c/resource-timing/issues/264
-    assert_less_than(Math.round(entry.startTime - timeBefore), delay * 1000, 'startTime should not expose redirect delays');
-}, "Verify that cross-origin resources don't implicitly expose their redirect timings")
+const timeBefore = performance.now();
+(async () => {
+  // Wait 10 ms, to ensure the difference between startTime and timeBefore is
+  // larger than 1 ms, to avoid flakiness in browsers that clamp timestamps to
+  // 1 ms.
+  await new Promise(r => step_timeout(r, 10));
+  attribute_test(load.iframe, destUrl, entry => {
+      assert_equals(entry.startTime, entry.fetchStart, 'startTime and fetchStart should be equal');
+      assert_greater_than(entry.startTime, timeBefore, 'startTime and fetchStart should be greater than the time before fetching');
+      // See https://github.com/w3c/resource-timing/issues/264
+      assert_less_than(Math.round(entry.startTime - timeBefore), delay * 1000, 'startTime should not expose redirect delays');
+  }, "Verify that cross-origin resources don't implicitly expose their redirect timings")
+})();
 
 </script>
 </body>
diff --git a/test/fixtures/wpt/resource-timing/delivery-type.tentative.any.js b/test/fixtures/wpt/resource-timing/delivery-type.tentative.any.js
new file mode 100644
index 000000000000000..e2b408fdd74f29f
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/delivery-type.tentative.any.js
@@ -0,0 +1,90 @@
+// META: global=window,worker
+// META: script=/common/get-host-info.sub.js
+// META: script=/resource-timing/resources/resource-loaders.js
+
+// TODO(crbug/1358591): Rename this file from "tentative" once
+// `w3c/resource-timing#343` is merged.
+
+const {REMOTE_ORIGIN, ORIGIN} = get_host_info();
+
+const redirectBase = new URL(
+  '/resource-timing/resources/redirect-cors.py', REMOTE_ORIGIN).href;
+const cacheAndValidatedBase = new URL(
+  '/resource-timing/resources/cacheable-and-validated.py?content=content',
+  ORIGIN).href;
+
+const mustRevalidate = {headers: {'Cache-Control': 'max-age=0'}};
+
+const fetchAndEatBody = (url, fetchOption) => {
+  return fetch(url, fetchOption).then(response => response.arrayBuffer());
+};
+
+const accumulateEntries = () => {
+  return new Promise(resolve => {
+    const po = new PerformanceObserver(list => {
+      resolve(list);
+    });
+    po.observe({type: "resource", buffered: true});
+  });
+};
+
+const checkDeliveryTypeBase =
+  (list, lookupURL, deliveryTypeForCachedResources) => {
+    const entries = list.getEntriesByName(lookupURL);
+    assert_equals(entries.length, 3, 'Wrong number of entries');
+
+    // 200 response (`cacheMode` is an empty string)
+    assert_equals(entries[0].deliveryType, "",
+      "Expect empty deliveryType for 200 response.");
+    // Cached response (`cacheMode` is "local") or 304 response (`cacheMode` is
+    // "validated").
+    assert_equals(entries[1].deliveryType, deliveryTypeForCachedResources,
+      `Expect "${deliveryTypeForCachedResources}" deliveryType for a
+        cached response.`);
+    assert_equals(entries[2].deliveryType, deliveryTypeForCachedResources,
+      `Expect "${deliveryTypeForCachedResources}" deliveryType for a
+        revalidated response.`);
+};
+
+promise_test(() => {
+  // Use a different URL every time so that the cache behaviour does not depend
+  // on execution order.
+  const initialURL = load.cache_bust(cacheAndValidatedBase);
+  const checkDeliveryType =
+    list => checkDeliveryTypeBase(list, initialURL, "cache");
+  return fetchAndEatBody(initialURL, {})                      // 200.
+    .then(() => fetchAndEatBody(initialURL, {}))              // Cached.
+    .then(() => fetchAndEatBody(initialURL, mustRevalidate))  // 304.
+    .then(accumulateEntries)
+    .then(checkDeliveryType);
+}, 'PerformanceResourceTiming deliveryType test, same origin.');
+
+promise_test(() => {
+  const cacheAndValidatedURL = load.cache_bust(
+    cacheAndValidatedBase + '&timing_allow_origin=*');
+  const redirectURL = redirectBase
+    + "?timing_allow_origin=*"
+    + `&allow_origin=${encodeURIComponent(ORIGIN)}`
+    + `&location=${encodeURIComponent(cacheAndValidatedURL)}`;
+  const checkDeliveryType =
+    list => checkDeliveryTypeBase(list, redirectURL, "cache");
+  return fetchAndEatBody(redirectURL, {})                      // 200.
+    .then(() => fetchAndEatBody(redirectURL, {}))              // Cached.
+    .then(() => fetchAndEatBody(redirectURL, mustRevalidate))  // 304.
+    .then(accumulateEntries)
+    .then(checkDeliveryType);
+}, 'PerformanceResourceTiming deliveryType test, cross origin, TAO passes.');
+
+promise_test(() => {
+  const cacheAndValidatedURL = load.cache_bust(cacheAndValidatedBase);
+  const redirectURL = redirectBase
+    + `?allow_origin=${encodeURIComponent(ORIGIN)}`
+    + `&location=${encodeURIComponent(cacheAndValidatedURL)}`;
+  const checkDeliveryType =
+    list => checkDeliveryTypeBase(list, redirectURL, "");
+  return fetchAndEatBody(redirectURL, {})                      // 200.
+    .then(() => fetchAndEatBody(redirectURL, {}))              // Cached.
+    .then(() => fetchAndEatBody(redirectURL, mustRevalidate))  // 304.
+    .then(accumulateEntries)
+    .then(checkDeliveryType);
+}, 'PerformanceResourceTiming deliveryType test, cross origin, TAO fails.');
diff --git a/test/fixtures/wpt/resource-timing/entries-for-network-errors.sub.https.html b/test/fixtures/wpt/resource-timing/entries-for-network-errors.sub.https.html
index 95849d282621ffc..ebc2247babcd4ab 100644
--- a/test/fixtures/wpt/resource-timing/entries-for-network-errors.sub.https.html
+++ b/test/fixtures/wpt/resource-timing/entries-for-network-errors.sub.https.html
@@ -30,6 +30,22 @@
 network_error_entry_test(
     `/element-timing/resources/multiple-redirects.py?redirect_count=22&final_resource=${validXmlUrl}`,
     null, "too many redirects");
+
+// ORB (https://github.com/whatwg/fetch/pull/1442) will return network errors
+// for certain cross-origin fetches. This tests that the same rules apply to
+// these fetches. Since ORB (at least as presently implemented) doesn't return
+// network errors for fetches, we have to load this case using an <img> element.
+//
+// This emulates a case previously tested in service-workers/service-worker/resource-timing.sub.https.html
+const orb_loader = (url, _) => new Promise(resolve => {
+  const img = document.createElement("img");
+  img.src = url;
+  img.onerror = resolve;
+  document.body.appendChild(img);
+} );
+network_error_entry_test(
+    '//{{hosts[alt][]}}:{{ports[https][0]}}/service-workers/service-worker/resources/missing.jpg',
+    null, "network error for ORB-blocked response", orb_loader);
 </script>
 </body>
 </html>
diff --git a/test/fixtures/wpt/resource-timing/fetch-cross-origin-redirect.https.html b/test/fixtures/wpt/resource-timing/fetch-cross-origin-redirect.https.html
index 4193422653a5954..1605e224ab43b2f 100644
--- a/test/fixtures/wpt/resource-timing/fetch-cross-origin-redirect.https.html
+++ b/test/fixtures/wpt/resource-timing/fetch-cross-origin-redirect.https.html
@@ -12,7 +12,7 @@
 
 const {REMOTE_ORIGIN, ORIGIN} = get_host_info();
 const redirect = "/common/redirect.py?" +
-                 "location=/resource-timing/resources/green.html";
+                 "location=/resource-timing/resources/empty_script.js";
 const cross_origin_redirect = REMOTE_ORIGIN + redirect;
 const same_origin_redirect = ORIGIN + redirect;
 
diff --git a/test/fixtures/wpt/resource-timing/iframe-failed-commit.html b/test/fixtures/wpt/resource-timing/iframe-failed-commit.html
index 1da207d2fbe05ee..d3b5cce59ec21e9 100644
--- a/test/fixtures/wpt/resource-timing/iframe-failed-commit.html
+++ b/test/fixtures/wpt/resource-timing/iframe-failed-commit.html
@@ -3,6 +3,7 @@
 <head>
 <meta charset="utf-8" />
 <title>Resource Timing - test that unsuccessful iframes create entries</title>
+<meta name="timeout" content="long">
 <link rel="author" title="Google" href="http://www.google.com/" />
 <link rel="help" href=
   "https://www.w3.org/TR/resource-timing-2/#resources-included-in-the-performanceresourcetiming-interface"/>
@@ -20,6 +21,10 @@
   return load.iframe_with_attrs(path, {"csp": "default-src 'none'"});
 };
 
+const load_iframe_with_csp_no_navigation = async path => {
+  return load.iframe_with_attrs(path, {"csp": "default-src 'none'"}, () => {}, true);
+}
+
 // Runs a test (labeled by the given label) to verify that loading an iframe
 // with the given URL generates a PerformanceResourceTiming entry and that the
 // entry does not expose sensitive timing attributes.
@@ -46,12 +51,12 @@
 };
 
 // Runs a test (labeled by the given label) to verify that loading an iframe
-// with the given URL, an empty response body and under a "default-src 'none'
-// Content-Security-Policy generates a PerformanceResourceTiming entry and that
-// the entry does expose sensitive timing attributes.
-const empty_unmasked_entry_with_csp_test = (url, label) => {
-  return attribute_test(load_iframe_with_csp, url,
-    invariants.assert_tao_pass_no_redirect_http_empty, label);
+// with the given URL under a "default-src 'none' Content-Security-Policy
+// generates a PerformanceResourceTiming entry and that the entry does not
+// expose sensitive timing attributes.
+const non_navigating_masked_entry_with_csp_test = (url, label) => {
+  return attribute_test(load_iframe_with_csp_no_navigation, url,
+    invariants.assert_tao_failure_resource, label);
 };
 
 const {REMOTE_ORIGIN, ORIGINAL_HOST, HTTPS_PORT} = get_host_info();
@@ -68,7 +73,8 @@
 unmasked_entry_with_csp_test("/resource-timing/resources/csp-default-none.html",
   "Same-origin iframe that complies with CSP attribute gets reported");
 
-unmasked_entry_with_csp_test("/resource-timing/resources/green-frame.html",
+// masked because this will load an error page which is cross-origin.
+masked_entry_with_csp_test("/resource-timing/resources/green-frame.html",
   "Same-origin iframe that doesn't comply with CSP attribute gets reported");
 
 masked_entry_with_csp_test(
@@ -79,7 +85,7 @@
   new URL("/resource-timing/resources/green-frame.html", REMOTE_ORIGIN),
   "Cross-origin iframe that doesn't comply with CSP attribute gets reported");
 
-empty_unmasked_entry_with_csp_test(
+masked_entry_with_csp_test(
   "/resource-timing/resources/200_empty.asis",
   "Same-origin empty iframe with a 200 status gets reported");
 
@@ -87,19 +93,19 @@
   new URL("/resource-timing/resources/200_empty.asis", REMOTE_ORIGIN),
   "Cross-origin empty iframe with a 200 status gets reported");
 
-unmasked_entry_with_csp_test(
-    new URL("/resource-timing/resources/204_empty.asis"),
+non_navigating_masked_entry_with_csp_test(
+    new URL("/resource-timing/resources/204_empty.asis", location.origin),
     "Same-origin empty iframe with a 204 status gets reported");
 
-unmasked_entry_with_csp_test(
-    new URL("/resource-timing/resources/205_empty.asis"),
+non_navigating_masked_entry_with_csp_test(
+    new URL("/resource-timing/resources/205_empty.asis", location.origin),
     "Same-origin empty iframe with a 205 status gets reported");
 
-masked_entry_with_csp_test(
+non_navigating_masked_entry_with_csp_test(
     new URL("/resource-timing/resources/204_empty.asis", REMOTE_ORIGIN),
     "Cross-origin empty iframe with a 204 status gets reported");
 
-masked_entry_with_csp_test(
+non_navigating_masked_entry_with_csp_test(
     new URL("/resource-timing/resources/205_empty.asis", REMOTE_ORIGIN),
     "Cross-origin empty iframe with a 205 status gets reported");
 
diff --git a/test/fixtures/wpt/resource-timing/iframe-sequence-of-events.html b/test/fixtures/wpt/resource-timing/iframe-sequence-of-events.html
index 5f99a5cab2de6b1..02d1c362c9df491 100644
--- a/test/fixtures/wpt/resource-timing/iframe-sequence-of-events.html
+++ b/test/fixtures/wpt/resource-timing/iframe-sequence-of-events.html
@@ -4,9 +4,21 @@
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="resources/frame-timing.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
 <body>
 <script>
   test_frame_timing_before_load_event('iframe');
-  test_frame_timing_change_src('iframe');
+
+  const host_info = get_host_info();
+  const types = ['ORIGIN', 'HTTP_REMOTE_ORIGIN', 'HTTP_NOTSAMESITE_ORIGIN'];
+  for (const a of types) {
+    for (const b of types) {
+      for (const tao of [true, false]) {
+        test_frame_timing_change_src('iframe', host_info[a], host_info[b], tao,
+        `Changing the src of an iframe (${a}->${b}) ${tao ? "with" : "without"} TAO should result in an RT entry`);
+      }
+    }
+  }
 </script>
-</body>
\ No newline at end of file
+</body>
diff --git a/test/fixtures/wpt/resource-timing/initiator-type/link.html b/test/fixtures/wpt/resource-timing/initiator-type/link.html
index c49576a8e650bc5..43367ac3d501e2c 100644
--- a/test/fixtures/wpt/resource-timing/initiator-type/link.html
+++ b/test/fixtures/wpt/resource-timing/initiator-type/link.html
@@ -1,38 +1,35 @@
 <!DOCTYPE html>
 <html>
+
 <head>
-<meta charset="utf-8" />
-<title>Resource Timing initiator type: link</title>
-<link rel="author" title="Google" href="http://www.google.com/" />
-<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script src="/resource-timing/resources/observe-entry.js"></script>
-<script src="resources/initiator-type-test.js"></script>
+  <meta charset="utf-8" />
+  <title>Resource Timing initiator type: link</title>
+  <link rel="author" title="Google" href="http://www.google.com/" />
+  <link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype" />
+  <link rel="stylesheet" href="/resource-timing/resources/nested.css">
+  <link rel="prefetch" href="/resource-timing/resources/resource_timing_test0.css?id=prefetch">
+  <link rel="preload" as="style" href="/resource-timing/resources/resource_timing_test0.css?id=preload">
+  <link rel="prerender" href="/resource-timing/resources/green.html?id=prerender">
+  <link rel="manifest" href="/resource-timing/resources/manifest.json">
+  <link rel="modulepreload" href="resources/empty.js?id=modulePreload">
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resource-timing/resources/observe-entry.js"></script>
+  <script src="resources/initiator-type-test.js"></script>
 </head>
 <body>
-<link rel="stylesheet" href="/resource-timing/resources/nested.css">
-<link rel="prefetch"
-    href="/resource-timing/resources/resource_timing_test0.css?id=prefetch">
-<link rel="preload" as="style"
-    href="/resource-timing/resources/resource_timing_test0.css?id=preload">
-<link rel="prerender" href="/resource-timing/resources/green.html?id=prerender">
-<link rel="manifest" href="/resource-timing/resources/manifest.json">
-<link rel="modulepreload" href="resources/empty.js?id=modulePreload">
-<script>
-  initiator_type_test("nested.css", "link", "<link>");
-
-  // Verify there are enries for each of nested.css' nested resources.
-  initiator_type_test("resource_timing_test0.css?id=n1", "css", "css resources embedded in css");
-  initiator_type_test("fonts/Ahem.ttf?id=n1", "css", "font resources embedded in css");
-  initiator_type_test("blue.png?id=n1", "css", "image resources embedded in css");
+  <script>
+    initiator_type_test("nested.css", "link", "<link>");
 
-  initiator_type_test("resource_timing_test0.css?id=prefetch", "link", "<link prefetch>");
-  initiator_type_test("resource_timing_test0.css?id=preload", "link", "<link preload>");
-  initiator_type_test("green.html?id=prerender", "link", "<link prerender>");
-  initiator_type_test("manifest.json", "link", "<link manifest>");
-  initiator_type_test("resources/empty.js?id=modulePreload", "other", "module preload");
-</script>
-<ol>This content forces a font to get fetched</ol>
+    // Verify there are enries for each of nested.css' nested resources.
+    initiator_type_test("resource_timing_test0.css?id=n1", "css", "css resources embedded in css");
+    initiator_type_test("fonts/Ahem.ttf?id=n1", "css", "font resources embedded in css");
+    initiator_type_test("blue.png?id=n1", "css", "image resources embedded in css");
+    initiator_type_test("resource_timing_test0.css?id=prefetch", "link", "<link prefetch>");
+    initiator_type_test("resource_timing_test0.css?id=preload", "link", "<link preload>");
+    initiator_type_test("manifest.json", "link", "<link manifest>");
+    initiator_type_test("resources/empty.js?id=modulePreload", "other", "module preload");
+  </script>
+  <ol>This content forces a font to get fetched</ol>
 </body>
 </html>
diff --git a/test/fixtures/wpt/resource-timing/initiator-type/script.html b/test/fixtures/wpt/resource-timing/initiator-type/script.html
index dbd6a131decae1b..6e9e3ae7eef361b 100644
--- a/test/fixtures/wpt/resource-timing/initiator-type/script.html
+++ b/test/fixtures/wpt/resource-timing/initiator-type/script.html
@@ -12,6 +12,7 @@
 </head>
 <body>
 <script src="/resource-timing/resources/empty_script.js"></script>
+<script type="module" src="/resource-timing/resources/parent_script.js"></script>
 <script>
   const async_xhr = new XMLHttpRequest;
   async_xhr.open('GET', '/resource-timing/resources/blue.png?id=async_xhr',
@@ -21,6 +22,7 @@
 <script>
   initiator_type_test("empty_script.js", "script", "<script>");
   initiator_type_test("blue.png?id=async_xhr", "xmlhttprequest", "an asynchronous XmlHTTPRequest");
+  initiator_type_test("child.js", "script", "script imported from another script");
 </script>
 </body>
 </html>
diff --git a/test/fixtures/wpt/resource-timing/initiator-type/video.html b/test/fixtures/wpt/resource-timing/initiator-type/video.html
index 16f3b3dea5f1e86..2d8c9dcc474c2c0 100644
--- a/test/fixtures/wpt/resource-timing/initiator-type/video.html
+++ b/test/fixtures/wpt/resource-timing/initiator-type/video.html
@@ -19,14 +19,14 @@
     src="/resource-timing/resources/empty.py?id=track">
 </video>
 <video autoplay="true">
-  <source src="/media/test.ogv?id=source-ogv" type="video/ogg">
+  <source src="/media/test.webm?id=source-webm" type="video/webm">
 </video>
 <script>
   initiator_type_test("blue.png?id=poster", "video", "<video poster>");
   initiator_type_test("media/test.mp4?id=src", "video", "<video src>");
   initiator_type_test("media/test.mp4?id=source-mp4", "video", "<source src> with type=\"video/mp4\"");
   initiator_type_test("empty.py?id=track", "track", "<track src>");
-  initiator_type_test("media/test.ogv?id=source-ogv", "video", "<source src> with type=\"video/ogg\"");
+  initiator_type_test("media/test.webm?id=source-webm", "video", "<source src> with type=\"video/webm\"");
 </script>
 </body>
 </html>
diff --git a/test/fixtures/wpt/resource-timing/initiator-type/workers.html b/test/fixtures/wpt/resource-timing/initiator-type/workers.html
index 3a23ad71a315558..a3da99356db5e21 100644
--- a/test/fixtures/wpt/resource-timing/initiator-type/workers.html
+++ b/test/fixtures/wpt/resource-timing/initiator-type/workers.html
@@ -17,7 +17,7 @@
   new Worker(moduleWorkerURL, {type: "module"});
   new Worker(workerURL, {type: "classic"});
   initiator_type_test(workerURL, "other", "classic worker");
-  initiator_type_test(moduleWorkerURL, "other", "module worker");
+  initiator_type_test(moduleWorkerURL, "script", "module worker");
 </script>
 </body>
 </html>
diff --git a/test/fixtures/wpt/resource-timing/interim-response-times.h2.html b/test/fixtures/wpt/resource-timing/interim-response-times.h2.html
new file mode 100644
index 000000000000000..4b1ca93ff7bd621
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/interim-response-times.h2.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name="timeout" content="long">
+<title>Resource Timing: PerformanceResourceTiming interim resource times</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<script src="/common/utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+  const {REMOTE_HOST} = get_host_info();
+  function interim_response_time_test({origin, with100, with103}) {
+    promise_test(async t => {
+      const delay = 500;
+      const url = new URL('/resource-timing/resources/header-delay.h2.py',
+      origin == "same-origin" ?
+          location.href :
+          `${location.protocol}//${REMOTE_HOST}:${location.port}`);
+      url.searchParams.set("delay", delay);
+      if (origin === "cross-origin-with-TAO")
+        url.searchParams.set("tao", "*");
+      if (with100)
+        url.searchParams.set("with100", "true");
+      if (with103)
+        url.searchParams.set("with103", "true");
+      const response = await fetch(url.toString(), {mode: "cors"});
+      assert_equals(response.status, 200)
+      await response.text();
+      const [entry] = performance.getEntriesByName(url.toString());
+      if (origin === "cross-origin") {
+        assert_equals(entry.firstInterimResponseStart, 0);
+        return;
+      }
+      let total_delay = entry.requestStart;
+      if (with100) {
+        total_delay += delay;
+        assert_greater_than(entry.firstInterimResponseStart,
+        total_delay,
+                            "firstInterimResponseStart > 100 response");
+      }
+
+      if (with103) {
+        total_delay += delay;
+        if (with100) {
+          assert_less_than_equal(entry.firstInterimResponseStart,
+          total_delay,  "firstInterimResponseStart > 100 response");
+        } else {
+          assert_greater_than(entry.firstInterimResponseStart,
+          delay, "firstInterimResponseStart > 100 response");
+        }
+      }
+
+      total_delay += delay;
+      if (!with100 && !with103)
+        assert_equals(entry.firstInterimResponseStart, 0);
+
+      assert_greater_than(entry.responseStart, total_delay,
+                        "responseStart");
+    }, `Fetch from ${origin} ${with103 ? "with" : "without"} early hints, ${
+        with100 ? "with" : "without"} 100 response`);
+  }
+
+  for (const with103 of [true, false]) {
+    for (const with100 of [true, false]) {
+      for (origin of ['same-origin', 'cross-origin', 'cross-origin-with-TAO']) {
+        interim_response_time_test({with100, with103, origin});
+      }
+    }
+  }
+</script>
+</body>
+</html>
diff --git a/test/fixtures/wpt/resource-timing/interim-response-times.html b/test/fixtures/wpt/resource-timing/interim-response-times.html
new file mode 100644
index 000000000000000..a4d03f599ee5a75
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/interim-response-times.html
@@ -0,0 +1,72 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name="timeout" content="long">
+<title>Resource Timing: PerformanceResourceTiming interim resource times</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<script src="/common/utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+  const {REMOTE_ORIGIN} = get_host_info();
+  function interim_response_time_test({origin, with100, with103}) {
+    promise_test(async t => {
+      const delay = 500;
+      const url = new URL('/resource-timing/resources/header-delay.py',
+        origin == "same-origin" ? location.href : REMOTE_ORIGIN);
+      url.searchParams.set("delay", delay);
+      if (origin === "cross-origin-with-TAO")
+        url.searchParams.set("tao", "*");
+      if (with100)
+        url.searchParams.set("with100", "true");
+      if (with103)
+        url.searchParams.set("with103", "true");
+      const response = await fetch(url.toString(), {mode: "cors"});
+      assert_equals(response.status, 200)
+      await response.text();
+      const [entry] = performance.getEntriesByName(url.toString());
+      if (origin === "cross-origin") {
+        assert_equals(entry.firstInterimResponseStart, 0);
+        return;
+      }
+      let total_delay = entry.requestStart;
+      if (with100) {
+        total_delay += delay;
+        assert_greater_than(entry.firstInterimResponseStart,
+        total_delay,
+                            "firstInterimResponseStart > 100 response");
+      }
+
+      if (with103) {
+        total_delay += delay;
+        if (with100) {
+          assert_less_than_equal(entry.firstInterimResponseStart,
+          total_delay,  "firstInterimResponseStart > 100 response");
+        } else {
+          assert_greater_than(entry.firstInterimResponseStart,
+          delay, "firstInterimResponseStart > 100 response");
+        }
+      }
+
+      total_delay += delay;
+      if (!with100 && !with103)
+        assert_equals(entry.firstInterimResponseStart, 0);
+
+      assert_greater_than(entry.responseStart, total_delay,
+                        "responseStart");
+    }, `Fetch from ${origin} ${with103 ? "with" : "without"} early hints, ${
+        with100 ? "with" : "without"} 100 response`);
+  }
+
+  for (const with103 of [true, false]) {
+    for (const with100 of [true, false]) {
+      for (origin of ['same-origin', 'cross-origin', 'cross-origin-with-TAO']) {
+        interim_response_time_test({with100, with103, origin});
+      }
+    }
+  }
+</script>
+</body>
+</html>
diff --git a/test/fixtures/wpt/resource-timing/internal-resources-not-counted.html b/test/fixtures/wpt/resource-timing/internal-resources-not-counted.html
new file mode 100644
index 000000000000000..a746e2adfa32bee
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/internal-resources-not-counted.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<meta charset="utf-8" />
+<title>Resource Timing should not include internal resources</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+
+<p>This test validates that image resources which are part of an element's
+UA-defined interface are not exposed to the performance timeline. This uses an
+&lt;audio&gt; element as an example of an element with internal resources used
+for the playback controls, and verifies that resource timing entries are not
+created.
+</p>
+
+<!-- This element will render with internal resources for playback controls -->
+<audio controls></audio>
+
+<script>
+  async_test(t => {
+  const observer = new PerformanceObserver(t.step_func_done(events => {
+    events.getEntries().forEach(entry => {
+      assert_true(entry.initiatorType == "script" || entry.initiatorType == "img",
+      "Resources loaded from this test should have initiatorType 'script' or 'img', but \"" +
+          entry.name + "\" has '" + entry.initiatorType + "'.");
+    });
+  }));
+
+  // Wait for one more resource to load before attaching listener, and then get
+  // buffered entries.
+  const image = document.createElement("img");
+  image.src = "resources/blue.png";
+  image.addEventListener("load", t.step_func(ev => {
+    observer.observe({type: "resource", buffered: true});
+  }));
+  document.body.appendChild(image);
+
+  }, "Resource timing should not include internal resources.");
+</script>
diff --git a/test/fixtures/wpt/resource-timing/nested-nav-fallback-timing.html b/test/fixtures/wpt/resource-timing/nested-nav-fallback-timing.html
new file mode 100644
index 000000000000000..b8bba5614d0d12b
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/nested-nav-fallback-timing.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test ResourceTiming reporting for cross-origin iframe.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/observe-entry.js"></script>
+</head>
+<body>
+<body>
+<script>
+  const {REMOTE_ORIGIN} = get_host_info();
+
+  promise_test(async t => {
+    const iframe = document.createElement('iframe');
+    t.add_cleanup(() => iframe.remove());
+    iframe.src = `${REMOTE_ORIGIN}/resource-timing/resources/delay-load.html`;
+    document.body.appendChild(iframe);
+    const entry = await observe_entry(iframe.src);
+    assert_greater_than(entry.duration, 1000);
+  }, "Cross-origin TAO-fail IFrame entries should report window load time");
+
+  promise_test(async t => {
+    const object = document.createElement('object');
+    object.type = "text/html";
+    t.add_cleanup(() => object.remove());
+    object.data = `${REMOTE_ORIGIN}/resource-timing/resources/delay-load.html`;
+    document.body.appendChild(object);
+    const entry = await observe_entry(object.data);
+    assert_greater_than(entry.duration, 1000);
+  }, "Cross-origin TAO-fail object entries should report window load time");
+
+  </script>
diff --git a/test/fixtures/wpt/resource-timing/no-entries-for-cross-origin-css-fetched-memory-cache.sub.html b/test/fixtures/wpt/resource-timing/no-entries-for-cross-origin-css-fetched-memory-cache.sub.html
new file mode 100644
index 000000000000000..6b60305ded2e997
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/no-entries-for-cross-origin-css-fetched-memory-cache.sub.html
@@ -0,0 +1,53 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>Make sure that resources fetched by cross origin CSS are not in the timeline.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<!--
+  This test is mostly the same as no-entries-for-cross-origin-css-fetched.html
+  but loads the sub-resources from another Document (<iframe>) earlier before
+  they are loaded via cross-origin CSSs, so that the resources are loaded from
+  cache and therefore no resource timing entries are created.
+-->
+
+<body>
+  <script>
+    const addLink = () => {
+      return new Promise(resolve => {
+        const link = document.createElement('LINK');
+        link.rel = 'stylesheet';
+        link.id = 'cross_origin_style';
+        link.href = 'http://{{hosts[][www1]}}:{{ports[http][1]}}/resource-timing/resources/nested.css';
+        link.addEventListener('load', resolve);
+        document.body.appendChild(link);
+      });
+    }
+
+    const addFrame = () => {
+      return new Promise(resolve => {
+        const iframe = document.createElement('iframe');
+        iframe.src = 'resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html';
+        iframe.addEventListener('load', resolve);
+        document.body.appendChild(iframe);
+      });
+    }
+
+    promise_test(async t => {
+      await addFrame();
+      await addLink();
+      // Assert no resource timing entries are created when the link is attached.
+      const url = (new URL(document.getElementById('cross_origin_style').href));
+      const prefix = url.protocol + '//' + url.host;
+      assert_equals(performance.getEntriesByName(
+        prefix + '/resource-timing/resources/resource_timing_test0.css?id=n1').length, 0,
+        'Import should not be in timeline');
+      assert_equals(performance.getEntriesByName(
+        prefix + '/fonts/Ahem.ttf?id=n1').length, 0, 'Font should not be in timeline');
+      assert_equals(performance.getEntriesByName(
+        prefix + '/resource-timing/resources/blue.png?id=n1').length, 0,
+        'Image should not be in timeline');
+    }, 'Make sure that resources fetched by cross origin CSS are not in the timeline.');
+  </script>
+  <ol>Some content</ol>
+</body>
diff --git a/test/fixtures/wpt/resource-timing/object-not-found-after-cross-origin-redirect.html b/test/fixtures/wpt/resource-timing/object-not-found-after-cross-origin-redirect.html
index 278c78e320e98ce..6990c6c06082e5d 100644
--- a/test/fixtures/wpt/resource-timing/object-not-found-after-cross-origin-redirect.html
+++ b/test/fixtures/wpt/resource-timing/object-not-found-after-cross-origin-redirect.html
@@ -4,6 +4,7 @@
 <meta charset="utf-8" />
 <title>This test validates the values in resource timing for cross-origin
 redirects.</title>
+<meta name="timeout" content="long">
 <link rel="author" title="Noam Rosenthal" href="noam@webkit.org">
 <link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
 <script src="/resources/testharness.js"></script>
@@ -15,20 +16,26 @@
 <body>
 <script>
 const {REMOTE_ORIGIN} = get_host_info();
-const delay = 2
+const delay = 1;
 const not_found_page = encodeURIComponent("/resource-timing/resources/status-code.py?status=404");
 const load_null_object = async path => {
   return load.object(path, null);
 }
-const destUrl = `/common/slow-redirect.py?delay=${delay}&location=${REMOTE_ORIGIN}/${not_found_page}`;
+const destUrl = `/common/slow-redirect.py?delay=${delay}&location=${REMOTE_ORIGIN}${not_found_page}`;
 
-const timeBefore = performance.now()
-attribute_test(load_null_object, destUrl, entry => {
-    assert_equals(entry.startTime, entry.fetchStart, 'startTime and fetchStart should be equal');
-    assert_greater_than(entry.startTime, timeBefore, 'startTime and fetchStart should be greater than the time before fetching');
-    // See https://github.com/w3c/resource-timing/issues/264
-    assert_less_than(Math.round(entry.startTime - timeBefore), delay * 1000, 'startTime should not expose redirect delays');
-}, "Verify that cross-origin object resources don't implicitly expose their redirect timings")
+const timeBefore = performance.now();
+(async () => {
+  // Wait 10 ms, to ensure the difference between startTime and timeBefore is
+  // larger than 1 ms, to avoid flakiness in browsers that clamp timestamps to
+  // 1 ms.
+  await new Promise(r => step_timeout(r, 10));
+  attribute_test(load_null_object, destUrl, entry => {
+      assert_equals(entry.startTime, entry.fetchStart, 'startTime and fetchStart should be equal');
+      assert_greater_than(entry.startTime, timeBefore, 'startTime and fetchStart should be greater than the time before fetching');
+      // See https://github.com/w3c/resource-timing/issues/264
+      assert_less_than(Math.round(entry.startTime - timeBefore), delay * 1000, 'startTime should not expose redirect delays');
+  }, "Verify that cross-origin object resources don't implicitly expose their redirect timings")
+})();
 
 </script>
 </body>
diff --git a/test/fixtures/wpt/resource-timing/queue-entry-regardless-buffer-size.html b/test/fixtures/wpt/resource-timing/queue-entry-regardless-buffer-size.html
new file mode 100644
index 000000000000000..ea47ae3a7950a23
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/queue-entry-regardless-buffer-size.html
@@ -0,0 +1,38 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<link rel="help" href="https://w3c.github.io/resource-timing/#dfn-mark-resource-timing">
+<title>This test validates that resource timing entires should always be queued regardless the size of the buffer.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async t => {
+    clearBufferAndSetSize(1);
+    let count = 0;
+    const allEntriesReceived =  new Promise(resolve => {
+      new PerformanceObserver(t.step_func((list) => {
+        for (const entry of list.getEntries()) {
+          if (entry.name.includes(scriptResources[0])) {
+            count += 1;
+          } else if (entry.name.includes(scriptResources[1])) {
+            count += 1;
+          }
+        }
+        if (count == 2) {
+          resolve();
+        }
+      })).observe({type: 'resource'});
+    });
+    load.script(scriptResources[0]);
+    load.script(scriptResources[1]);
+
+    // Two resource timing entries should be observed regardless the
+    // fact that we've set the buffer size to 1.
+    await allEntriesReceived;
+}, "Test that buffer size has no impact to whether an entry is queued or not");
+</script>
diff --git a/test/fixtures/wpt/resource-timing/resource-timing-failed-fetch-web-bundle.tentative.html b/test/fixtures/wpt/resource-timing/resource-timing-failed-fetch-web-bundle.tentative.html
new file mode 100644
index 000000000000000..b99183a49cd84c2
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resource-timing-failed-fetch-web-bundle.tentative.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<meta charset="utf-8" />
+<title>
+  Resource timing attributes are consistent for the same-origin subresources.
+</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/web-bundle/resources/test-helpers.js"></script>
+
+<body>
+  <script>
+    setup(() => {
+      assert_true(HTMLScriptElement.supports("webbundle"));
+    });
+
+    promise_test(async (t) => {
+      const script_url = 'dynamic1:resource1.js';
+      const non_exist_script_url = 'dynamic1:non_exist_resource.js';
+      // Using functions from /web-bundle/resources/test-helpers.js.
+      const element = createWebBundleElement(
+        "../web-bundle/resources/wbn/dynamic1.wbn",
+        /*resources=*/[script_url]
+      );
+
+      document.body.appendChild(element);
+
+      // Fetch the script that is in the web bundle.
+      const script = document.createElement("script");
+      script.type = "module";
+      script.src = script_url;
+      document.body.appendChild(script);
+
+      // Fetch the script that is not in the web bundle.
+      // Using functions from /web-bundle/resources/test-helpers.js.
+      await fetchAndWaitForReject(non_exist_script_url);
+
+      let resource1_entries = [];
+      let non_exist_resource_entries = [];
+
+      await new Promise((resolve) => {
+        new PerformanceObserver(list => {
+          resource1_entries.push(list.getEntries().filter(e => e.name.includes('resource1.js')));
+          non_exist_resource_entries.push(
+            list.getEntries().filter(e => e.name.includes('non_exist_resource.js')));
+          if (resource1_entries.length == 1 && non_exist_resource_entries.length == 1) {
+            resolve();
+          }
+        }
+        ).observe({ type: 'resource', buffered: true });
+      });
+    }, "Web bundle resources should have resource timing entries, even when the fetch failed.");
+  </script>
+</body>
\ No newline at end of file
diff --git a/test/fixtures/wpt/resource-timing/resource-timing-failed-fetch.html b/test/fixtures/wpt/resource-timing/resource-timing-failed-fetch.html
new file mode 100644
index 000000000000000..5bab39e2760728a
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resource-timing-failed-fetch.html
@@ -0,0 +1,34 @@
+<!doctype html>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<link rel="stylesheet" href="resources/empty_style.css">
+<link rel="stylesheet" href="resources/non_exist.css">
+
+<script>
+  promise_test(async () => {
+    const css_resource_timing_entries = await new Promise(resolve => {
+      new PerformanceObserver((list, observer) => {
+        let css_resource_timing_entries = list.getEntries().filter(e => e.name.includes('css'));
+        if (css_resource_timing_entries.length >= 2) {
+          resolve(css_resource_timing_entries);
+        }
+      }).observe({ 'type': 'resource', 'buffered': true });
+    });
+
+    assert_equals(css_resource_timing_entries.length, 2,
+      'There should be two resource timing entries for css resources');
+
+    assert_equals(css_resource_timing_entries.filter(
+      e => e.name.includes('empty_style.css')).length, 1,
+      'There should be one resource timing entry for successfully fetched resource.');
+
+    assert_equals(css_resource_timing_entries.filter(
+      e => e.name.includes('non_exist.css')).length, 1,
+      'There should be one resource timing entry for fetching failed resource.');
+
+  }, 'Resource fetched by HTTP protocol should have resource timing entry emitted, \
+  even when the fetch failed.');
+</script>
+
+</html>
\ No newline at end of file
diff --git a/test/fixtures/wpt/resource-timing/resource-timing-level1.js b/test/fixtures/wpt/resource-timing/resource-timing-level1.js
index 95b5cdfb1ed0ca2..6167777fe68fa3d 100644
--- a/test/fixtures/wpt/resource-timing/resource-timing-level1.js
+++ b/test/fixtures/wpt/resource-timing/resource-timing-level1.js
@@ -235,47 +235,6 @@ window.onload =
                 });
             });
 
-        // Test that responseStart uses the timing of 1XX responses by
-        // synthesizing a delay between a 100 and 200 status, and verifying that
-        // this delay is included before responseEnd. If the delay is not
-        // included, this implies that the 200 status line was (incorrectly) used
-        // for responseStart timing, despite the 100 response arriving earlier.
-        //
-        // Source: "In the case where more than one response is available for a
-        // request, due to an Informational 1xx response, the reported
-        // responseStart value is that of the first response to the last
-        // request."
-        [
-            { initiator: "iframe",         response: "(done)",    mime: mimeHtml },
-            { initiator: "xmlhttprequest", response: "(done)",    mime: mimeText },
-            { initiator: "script",         response: '"";',       mime: mimeScript },
-            { initiator: "link",           response: ".unused{}", mime: mimeCss },
-        ]
-        .forEach(function (template) {
-            testCases.push({
-                description: "'" + template.initiator + " responseStart uses 1XX (first) response timings'",
-                test: function (test) {
-                    initiateFetch(
-                        test,
-                        template.initiator,
-                        getSyntheticUrl("status:100"
-                                        + "&flush"
-                                        + "&" + serverStepDelay + "ms"
-                                        + "&status:200"
-                                        + "&mime:" + template.mime
-                                        + "&send:" + encodeURIComponent(template.response)),
-                        function (initiator, entry) {
-                            assert_greater_than_equal(
-                                entry.responseEnd,
-                                entry.responseStart + serverStepDelay,
-                                "HTTP/1.1 1XX (first) response should determine 'responseStart' timing.");
-
-                            test.done();
-                        });
-                    }
-                });
-            });
-
         // Function to run the next case in the queue.
         var currentTestIndex = -1;
         function runNextCase() {
diff --git a/test/fixtures/wpt/resource-timing/resources/child_script.js b/test/fixtures/wpt/resource-timing/resources/child_script.js
new file mode 100644
index 000000000000000..8b137891791fe96
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resources/child_script.js
@@ -0,0 +1 @@
+
diff --git a/test/fixtures/wpt/resource-timing/resources/delay-load.html b/test/fixtures/wpt/resource-timing/resources/delay-load.html
new file mode 100644
index 000000000000000..4898c1be8ebfff9
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resources/delay-load.html
@@ -0,0 +1,4 @@
+<!DOCTYPE html>
+<body>
+<img src="/images/blue.png?pipe=trickle(d1)">
+</body>
diff --git a/test/fixtures/wpt/resource-timing/resources/entry-invariants.js b/test/fixtures/wpt/resource-timing/resources/entry-invariants.js
index 4bef9496103ca61..78d43d1b01e4516 100644
--- a/test/fixtures/wpt/resource-timing/resources/entry-invariants.js
+++ b/test/fixtures/wpt/resource-timing/resources/entry-invariants.js
@@ -1,3 +1,19 @@
+const await_with_timeout = async (delay, message, promise, cleanup = ()=>{}) => {
+  let timeout_id;
+  const timeout = new Promise((_, reject) => {
+    timeout_id = step_timeout(() =>
+      reject(new DOMException(message, "TimeoutError")), delay)
+  });
+  let result = null;
+  try {
+    result = await Promise.race([promise, timeout]);
+    clearTimeout(timeout_id);
+  } finally {
+    cleanup();
+  }
+  return result;
+};
+
 // Asserts that the given attributes are present in 'entry' and hold equal
 // values.
 const assert_all_equal_ = (entry, attributes) => {
@@ -75,8 +91,6 @@ const invariants = {
     assert_positive_(entry, [
       "fetchStart",
       "transferSize",
-      "encodedBodySize",
-      "decodedBodySize",
     ]);
   },
 
@@ -98,8 +112,6 @@ const invariants = {
       "secureConnectionStart",
       "redirectStart",
       "redirectEnd",
-      "encodedBodySize",
-      "decodedBodySize",
     ]);
 
     assert_not_negative_(entry, [
@@ -139,8 +151,6 @@ const invariants = {
     assert_positive_(entry, [
       "fetchStart",
       "transferSize",
-      "encodedBodySize",
-      "decodedBodySize",
     ]);
   },
 
@@ -172,8 +182,6 @@ const invariants = {
     assert_positive_(entry, [
       "fetchStart",
       "transferSize",
-      "encodedBodySize",
-      "decodedBodySize",
     ]);
   },
 
@@ -196,8 +204,6 @@ const invariants = {
       "secureConnectionStart",
       "redirectStart",
       "redirectEnd",
-      "encodedBodySize",
-      "decodedBodySize",
     ]);
 
     assert_not_negative_(entry, [
@@ -229,8 +235,6 @@ const invariants = {
       "workerStart",
       "redirectStart",
       "redirectEnd",
-      "encodedBodySize",
-      "decodedBodySize",
     ]);
 
     assert_not_negative_(entry, [
@@ -405,8 +409,6 @@ const invariants = {
       "requestStart",
       "responseStart",
       "transferSize",
-      "encodedBodySize",
-      "decodedBodySize",
     ]);
 
     assert_ordered_(entry, [
@@ -440,8 +442,6 @@ const invariants = {
       "requestStart",
       "responseStart",
       "transferSize",
-      "encodedBodySize",
-      "decodedBodySize",
     ]);
   }
 
@@ -467,7 +467,10 @@ const attribute_test_internal = (loader, path, validator, run_test, test_label)
       });
 
       await loader(path, validator);
-      const entry = await(loaded_entry);
+      const entry = await await_with_timeout(2000,
+        "Timeout was reached before entry fired",
+        loaded_entry);
+      assert_not_equals(entry, null, 'No entry was received');
       run_test(entry);
   }, test_label);
 };
@@ -485,11 +488,13 @@ const attribute_test_with_validator = (loader, path, validator, run_test, test_l
   attribute_test_internal(loader, path, validator, run_test, test_label);
 };
 
-const network_error_entry_test = (originalURL, args, label) => {
+const network_error_entry_test = (originalURL, args, label, loader) => {
   const url = new URL(originalURL, location.href);
   const search = new URLSearchParams(url.search.substr(1));
   const timeBefore = performance.now();
-  loader = () => new Promise(resolve => fetch(url, args).catch(resolve));
+
+  // Load using `fetch()`, unless we're given a specific loader for this test.
+  loader ??= () => new Promise(resolve => fetch(url, args).catch(resolve));
 
   attribute_test(
     loader, url,
diff --git a/test/fixtures/wpt/resource-timing/resources/frame-timing.js b/test/fixtures/wpt/resource-timing/resources/frame-timing.js
index e0c364e9b2c3e26..019bd424b550654 100644
--- a/test/fixtures/wpt/resource-timing/resources/frame-timing.js
+++ b/test/fixtures/wpt/resource-timing/resources/frame-timing.js
@@ -1,48 +1,63 @@
 function test_frame_timing_before_load_event(type) {
-    promise_test(async t => {
-        const {document, performance} = type === 'frame' ? window.parent : window;
-        const delay = 500;
-        const frame = document.createElement(type);
-        t.add_cleanup(() => frame.remove());
-        await new Promise(resolve => {
-            frame.addEventListener('load', resolve);
-            frame.src = `resources/iframe-with-delay.sub.html?delay=${delay}`;
-            (type === 'frame' ? document.querySelector('frameset') : document.body).appendChild(frame);
-        });
+  promise_test(async t => {
+    const {document, performance} = type === 'frame' ? window.parent : window;
+    const delay = 500;
+    const frame = document.createElement(type);
+    t.add_cleanup(() => frame.remove());
+    await new Promise(resolve => {
+      frame.addEventListener('load', resolve);
+      frame.src = `/resource-timing/resources/iframe-with-delay.sub.html?delay=${delay}`;
+      (type === 'frame' ? document.querySelector('frameset') : document.body).appendChild(frame);
+    });
 
-        const entries = performance.getEntriesByName(frame.src);
-        const navigationEntry = frame.contentWindow.performance.getEntriesByType('navigation')[0];
-        assert_equals(entries.length, 1);
-        assert_equals(entries[0].initiatorType, type);
-        assert_greater_than(performance.now(), entries[0].responseEnd + delay);
-        const domContentLoadedEventAbsoluteTime = navigationEntry.domContentLoadedEventStart + frame.contentWindow.performance.timeOrigin;
-        const frameResponseEndAbsoluteTime = entries[0].responseEnd + performance.timeOrigin;
-        assert_greater_than(domContentLoadedEventAbsoluteTime, frameResponseEndAbsoluteTime);
-    }, `A ${type} should report its RT entry when the response is done and before it is completely loaded`);
+    const entries = performance.getEntriesByName(frame.src);
+    const navigationEntry = frame.contentWindow.performance.getEntriesByType('navigation')[0];
+    assert_equals(entries.length, 1);
+    assert_equals(entries[0].initiatorType, type);
+    assert_greater_than(performance.now(), entries[0].responseEnd + delay);
+    const domContentLoadedEventAbsoluteTime =
+      navigationEntry.domContentLoadedEventStart +
+      frame.contentWindow.performance.timeOrigin;
+    const frameResponseEndAbsoluteTime = entries[0].responseEnd + performance.timeOrigin;
+    assert_greater_than(domContentLoadedEventAbsoluteTime, frameResponseEndAbsoluteTime);
+  }, `A ${type} should report its RT entry when the response is done and before it is completely loaded`);
 }
 
 
-function test_frame_timing_change_src(type) {
-    promise_test(async t => {
-        const {document, performance} = type === 'frame' ? window.parent : window;
-        const frame = document.createElement(type);
-        t.add_cleanup(() => frame.remove());
-        await new Promise(resolve => {
-          const done = () => {
-            resolve();
-            frame.removeEventListener('load', done);
-          }
-          frame.addEventListener('load', done);
-          frame.src = 'resources/green.html?1';
-            (type === 'frame' ? document.querySelector('frameset') : document.body).appendChild(frame);
-        });
+function test_frame_timing_change_src(type,
+                                      origin1 = document.origin,
+                                      origin2 = document.origin,
+                                      tao = false, label = '') {
+  const uid = token();
+  promise_test(async t => {
+    const {document, performance} = type === 'frame' ? window.parent : window;
+    const frame = document.createElement(type);
+    t.add_cleanup(() => frame.remove());
+    function createURL(origin) {
+      const url = new URL(`${origin}/resource-timing/resources/green.html`, location.href);
+      url.searchParams.set("uid", uid);
+      if (tao)
+        url.searchParams.set("pipe", "header(Timing-Allow-Origin, *)");
+      return url.toString();
+    }
 
-        await new Promise(resolve => {
-          frame.addEventListener('load', resolve);
-          frame.src = 'resources/green.html?2';
-        });
+    await new Promise(resolve => {
+      const done = () => {
+        resolve();
+        frame.removeEventListener('load', done);
+      }
+      frame.addEventListener('load', done);
+      frame.src = createURL(origin1);
+      const root = type === 'frame' ? document.querySelector('frameset') : document.body;
+      root.appendChild(frame);
+    });
 
-        const entries = performance.getEntries().filter(e => e.name.includes('green.html'));
-        assert_equals(entries.length, 2);
-      }, `A ${type} should report separate RT entries if its src changed from the outside`);
-}
\ No newline at end of file
+    await new Promise(resolve => {
+      frame.addEventListener('load', resolve);
+      frame.src = createURL(origin2);
+    });
+
+    const entries = performance.getEntries().filter(e => e.name.includes(uid));
+    assert_equals(entries.length, 2);
+  }, label || `A ${type} should report separate RT entries if its src changed from the outside`);
+}
diff --git a/test/fixtures/wpt/resource-timing/resources/get-resourceID.js b/test/fixtures/wpt/resource-timing/resources/get-resourceID.js
new file mode 100644
index 000000000000000..3fe499226a405d1
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resources/get-resourceID.js
@@ -0,0 +1,30 @@
+function getResourceID(resourceName) {
+  return new Promise((resolve) => {
+    const observer = new PerformanceObserver((list) => {
+      const entries = list.getEntriesByType("resource");
+      for (const entry of entries) {
+        if (entry.name.endsWith(resourceName)) {
+          observer.disconnect();
+          resolve(`${entry.name}/${entry.startTime}`);
+          return;
+        }
+      }
+    });
+    observer.observe({ entryTypes: ["resource"] });
+  });
+}
+
+function getDocumentResourceID() {
+  return new Promise((resolve) => {
+    const observer = new PerformanceObserver((list) => {
+      const entries = list.getEntriesByType("navigation");
+      if (entries.length > 0) {
+        observer.disconnect();
+        const [entry] = entries;
+        const { name, startTime } = entry;
+        resolve(`${name}/${startTime}`);
+      }
+    });
+    observer.observe({ entryTypes: ["navigation"] });
+  });
+}
diff --git a/test/fixtures/wpt/resource-timing/resources/loadingResources.js b/test/fixtures/wpt/resource-timing/resources/loadingResources.js
new file mode 100644
index 000000000000000..e5d5d71982af058
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resources/loadingResources.js
@@ -0,0 +1,21 @@
+//Fetching the Stylesheet
+var link = document.createElement("link");
+link.rel = "stylesheet";
+link.href = "../resources/empty_style.css";
+document.head.appendChild(link);
+
+// Fetching an image
+var img = document.createElement("img");
+img.src = "/images/blue.png";
+img.alt = "Sample Image for testing initiator Attribute";
+document.body.appendChild(img);
+
+//Inserting a html document in an iframe
+var iframe = document.createElement("iframe");
+iframe.src = "../resources/green.html";
+document.body.appendChild(iframe);
+
+// Inserting a script element
+var script = document.createElement("script");
+script.src = "../resources/empty.js";
+document.body.appendChild(script);
diff --git a/test/fixtures/wpt/resource-timing/resources/nested-contexts.js b/test/fixtures/wpt/resource-timing/resources/nested-contexts.js
index c0822943e86a68f..31337ae5da2e181 100644
--- a/test/fixtures/wpt/resource-timing/resources/nested-contexts.js
+++ b/test/fixtures/wpt/resource-timing/resources/nested-contexts.js
@@ -22,22 +22,12 @@ const post_refresh_url =
 
 const setup_navigate_or_refresh = (type, pre, post) => {
   const verify_document_navigate_not_observable = () => {
-    const entries = performance.getEntriesByType("resource");
-    let found_first_document = false;
-    for (entry of entries) {
-      if (entry.name == pre) {
-        found_first_document = true;
-      }
-      if (entry.name == post) {
-        opener.postMessage(`FAIL - ${type} document should not be observable`,
-          `*`);
-        return;
-      }
-    }
-    if (!found_first_document) {
-      opener.postMessage("FAIL - initial document should be observable", "*");
-      return;
+    if (performance.getEntriesByName(post).length) {
+      opener.postMessage(`FAIL - ${type} document should not be observable`,
+      `*`);
+
     }
+
     opener.postMessage("PASS", "*");
   }
   window.addEventListener("message", e => {
@@ -57,21 +47,8 @@ const setup_refresh_test = () => {
 
 const setup_back_navigation = pushed_url => {
   const verify_document_navigate_not_observable = navigated_back => {
-    const entries = performance.getEntriesByType("resource");
-    let found_first_document = false;
-    for (entry of entries) {
-      if (entry.name == pre_navigate_url) {
-        found_first_document = true;
-      }
-      if (entry.name == post_navigate_url) {
-        opener.postMessage("FAIL - navigated document exposed", "*");
-        return;
-      }
-    }
-    if (!found_first_document) {
-      opener.postMessage(`FAIL - first document not exposed. navigated_back ` +
-        `is ${navigated_back}`, "*");
-      return;
+    if (performance.getEntriesByName(post_navigate_url).length) {
+      opener.postMessage("FAIL - navigated document exposed", "*");
     }
     if (navigated_back) {
       opener.postMessage("PASS", "*");
diff --git a/test/fixtures/wpt/resource-timing/resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html b/test/fixtures/wpt/resource-timing/resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html
new file mode 100644
index 000000000000000..f47913468b68eb2
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html
@@ -0,0 +1,8 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<link rel="stylesheet" href="http://{{hosts[][www1]}}:{{ports[http][1]}}/resource-timing/resources/nested.css">
+</head>
+<body>
+<ol>Some content</ol>
+</body>
diff --git a/test/fixtures/wpt/resource-timing/resources/parent_script.js b/test/fixtures/wpt/resource-timing/resources/parent_script.js
new file mode 100644
index 000000000000000..01ec0c5823de978
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resources/parent_script.js
@@ -0,0 +1 @@
+import './child.js';
diff --git a/test/fixtures/wpt/resource-timing/resources/resource-loaders.js b/test/fixtures/wpt/resource-timing/resources/resource-loaders.js
index 99a2c28d2b3b27d..37fea16b1750faa 100644
--- a/test/fixtures/wpt/resource-timing/resources/resource-loaders.js
+++ b/test/fixtures/wpt/resource-timing/resources/resource-loaders.js
@@ -1,23 +1,38 @@
 const load = {
-  _cache_bust_value: Math.random().toString().substr(2),
 
   cache_bust: path => {
     let url = new URL(path, location.origin);
     url.href += (url.href.includes("?")) ? '&' : '?';
-    url.href += "unique=" + load._cache_bust_value++
+    // The `Number` type in Javascript, when interpreted as an integer, can only
+    // safely represent [-2^53 + 1, 2^53 - 1] without the loss of precision [1].
+    // We do not generate a global value and increment from it, as the increment
+    // might not have enough precision to be reflected.
+    //
+    // [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number
+    url.href += "unique=" + Math.random().toString().substring(2);
     return url.href;
   },
 
-  // Returns a promise that settles once the given path has been fetched as an
-  // image resource.
-  image: path => {
+  image_with_attrs: async (path, attribute_map) => {
     return new Promise(resolve => {
       const img = new Image();
+      for (const key in attribute_map)
+          img[key] = attribute_map[key];
       img.onload = img.onerror = resolve;
       img.src = load.cache_bust(path);
     });
   },
 
+  // Returns a promise that settles once the given path has been fetched as an
+  // image resource.
+  image: path => {
+    return load.image_with_attrs(path, undefined);
+  },
+
+  // Returns a promise that settles once the given path has been fetched as an
+  // image resource.
+  image_cors: path => load.image_with_attrs(path, {crossOrigin: "anonymous"}),
+
   // Returns a promise that settles once the given path has been fetched as a
   // font resource.
   font: path => {
@@ -37,10 +52,13 @@ const load = {
     });
   },
 
-  // Returns a promise that settles once the given path has been fetched as a
-  // stylesheet resource.
-  stylesheet: async path => {
+  stylesheet_with_attrs: async (path, attribute_map) => {
     const link = document.createElement("link");
+    if (attribute_map instanceof Object) {
+      for (const [key, value] of Object.entries(attribute_map)) {
+        link[key] = value;
+      }
+    }
     link.rel = "stylesheet";
     link.type = "text/css";
     link.href = load.cache_bust(path);
@@ -54,7 +72,13 @@ const load = {
     document.head.removeChild(link);
   },
 
-  iframe_with_attrs: async (path, attribute_map, validator) => {
+  // Returns a promise that settles once the given path has been fetched as a
+  // stylesheet resource.
+  stylesheet: async path => {
+    return load.stylesheet_with_attrs(path, undefined);
+  },
+
+  iframe_with_attrs: async (path, attribute_map, validator, skip_wait_for_navigation) => {
     const frame = document.createElement("iframe");
     if (attribute_map instanceof Object) {
       for (const [key, value] of Object.entries(attribute_map)) {
@@ -66,11 +90,17 @@ const load = {
     });
     frame.src = load.cache_bust(path);
     document.body.appendChild(frame);
-    await loaded;
+    if ( !skip_wait_for_navigation ) {
+      await loaded;
+    }
     if (validator instanceof Function) {
       validator(frame);
     }
-    document.body.removeChild(frame);
+    // since we skipped the wait for load animation, we cannot
+    // remove the iframe here since the request could get cancelled
+    if ( !skip_wait_for_navigation ) {
+      document.body.removeChild(frame);
+    }
   },
 
   // Returns a promise that settles once the given path has been fetched as an
@@ -79,10 +109,13 @@ const load = {
     return load.iframe_with_attrs(path, undefined, validator);
   },
 
-  // Returns a promise that settles once the given path has been fetched as a
-  // script.
-  script: async path => {
+  script_with_attrs: async (path, attribute_map) => {
     const script = document.createElement("script");
+    if (attribute_map instanceof Object) {
+      for (const [key, value] of Object.entries(attribute_map)) {
+        script[key] = value;
+      }
+    }
     const loaded = new Promise(resolve => {
       script.onload = script.onerror = resolve;
     });
@@ -92,21 +125,29 @@ const load = {
     document.body.removeChild(script);
   },
 
+  // Returns a promise that settles once the given path has been fetched as a
+  // script.
+  script: async path => {
+    return load.script_with_attrs(path, undefined);
+  },
+
   // Returns a promise that settles once the given path has been fetched as an
   // object.
   object: async (path, type) => {
     const object = document.createElement("object");
-    const loaded = new Promise(resolve => {
+    const object_load_settled = new Promise(resolve => {
       object.onload = object.onerror = resolve;
     });
     object.data = load.cache_bust(path);
     if (type) {
       object.type = type;
     }
-    object.style = "width: 0px; height: 0px";
     document.body.appendChild(object);
-    await loaded;
-    document.body.removeChild(object);
+    await await_with_timeout(2000,
+      "Timeout was reached before load or error events fired",
+      object_load_settled,
+      () => { document.body.removeChild(object) }
+    );
   },
 
   // Returns a promise that settles once the given path has been fetched
diff --git a/test/fixtures/wpt/resource-timing/resources/test-initiator.js b/test/fixtures/wpt/resource-timing/resources/test-initiator.js
new file mode 100644
index 000000000000000..f839b463c56d8f7
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/resources/test-initiator.js
@@ -0,0 +1,16 @@
+function testResourceInitiator(resourceName, expectedInitiator) {
+    return new Promise(resolve => {
+      const observer = new PerformanceObserver(list => {
+        const entries = list.getEntriesByType('resource');
+        for (const entry of entries) {
+          if (entry.name.endsWith(resourceName)) {
+            observer.disconnect();
+            assert_equals(entry.initiator, expectedInitiator, `Test ${resourceName} initiator`);
+            resolve();
+            return;
+          }
+        }
+      });
+      observer.observe({entryTypes: ['resource']});
+    });
+}
\ No newline at end of file
diff --git a/test/fixtures/wpt/resource-timing/response-status-code.html b/test/fixtures/wpt/resource-timing/response-status-code.html
new file mode 100644
index 000000000000000..3a184c6f016b28c
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/response-status-code.html
@@ -0,0 +1,165 @@
+<!DOCTYPE html>
+<head>
+<meta charset="utf-8" />
+<meta name="timeout" content="long">
+<title>This test validates the response status of resources.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+</head>
+<body>
+<script>
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+const SAME_ORIGIN = location.origin;
+const status_codes = [
+  200, 203,
+  400, 401, 403, 404,
+  500, 501, 502, 503,
+];
+
+const load_image_object = async path => {
+  return load.object(path, "image/png");
+}
+
+const load_frame_object = async path => {
+  return load.object(path, "text/html");
+}
+
+const load_null_object = async path => {
+  return load.object(path, null);
+}
+
+// Response status for same origin resources is exposed.
+for(const loader of [
+  load.font,
+  load.image,
+  load.script,
+  load.stylesheet,
+  load.xhr_sync,
+  load.xhr_async,
+  load.iframe,
+  load_image_object,
+  load_frame_object,
+  load_null_object
+]) {
+  for(const status of status_codes) {
+    let path = (loader == load.font) ? '/fonts/pass.woff' :
+                                       '/resource-timing/resources/empty.js';
+    path += `?pipe=status(${status})`;
+    attribute_test(
+      loader, new URL(path, ORIGIN),
+      entry => {
+        assert_equals(entry.responseStatus, status,
+          `response status for ${entry.name} should be ${status}`);
+      }
+    );
+  }
+}
+
+// Response status is exposed for CORS requests for cross-origin resources.
+for(const loader of [
+  load.image_with_attrs,
+  load.script_with_attrs,
+  load.stylesheet_with_attrs
+]) {
+  for(const status of status_codes) {
+    const path = `/resource-timing/resources/empty.js?pipe=status(${status})`
+      + `|header(access-control-allow-origin, ${ORIGIN})`;
+    loader_with_crossOrigin_attr = async url => {
+      return loader(url, {"crossOrigin": "anonymous"});
+    }
+    attribute_test(
+      loader_with_crossOrigin_attr, new URL(path, REMOTE_ORIGIN),
+      entry => {
+        assert_equals(entry.responseStatus, status,
+          `response status for ${entry.name} should be ${status}`);
+      }
+    );
+  }
+}
+
+// Response status is 0 when a no-cors request is made for cross origin
+// fonts, images, scripts, stylesheets.
+// Response status is 0 when request's mode is "navigate" and response's
+// URL's origin is not same origin with request's origin. So response
+// status is not exposed for cross origin iframes.
+for(const loader of [
+  load.font,
+  load.image,
+  load.script,
+  load.stylesheet,
+  load.iframe,
+  load_image_object,
+  load_frame_object,
+  load_null_object
+]) {
+  for(const tao of [false, true]) {
+    for(const status of status_codes) {
+      let path = (loader == load.font) ? '/fonts/pass.woff' :
+                                         '/resource-timing/resources/empty.js';
+      path += `?pipe=status(${status})`;
+      if (tao) {
+        path += `|header(timing-allow-origin, *)`;
+      }
+      attribute_test(
+        loader, new URL(path, REMOTE_ORIGIN),
+        entry => {
+          assert_equals(entry.responseStatus, 0,
+            `response status for ${entry.name} should be 0`);
+        }
+      );
+    }
+  }
+}
+
+// Response status for iframes is 0 when cross origin redirects are present
+// Same-Origin => Cross-Origin => Same-Origin => Same-Origin redirect chain
+for(const loader of [
+  load.iframe,
+  load_frame_object,
+  load_null_object
+]) {
+  for(const status of status_codes) {
+    const destUrl =
+      `${SAME_ORIGIN}/resource-timing/resources/multi_redirect.py` +
+        `?page_origin=${SAME_ORIGIN}` +
+        `&cross_origin=${REMOTE_ORIGIN}` +
+        `&final_resource=` +
+        `/resource-timing/resources/empty.js?pipe=status(${status})`;
+    attribute_test(
+      loader, new URL(destUrl),
+      entry => {
+        assert_equals(entry.responseStatus, 0,
+          `response status should be 0 for iframes having cross origin`
+          + ` redirects`);
+      }
+    );
+  }
+}
+
+// Response status for iframes is exposed for same origin redirects
+for(const loader of [
+  load.iframe,
+  load_frame_object,
+  load_null_object
+]) {
+  for(const status of status_codes) {
+    const destUrl = `${SAME_ORIGIN}/resource-timing/resources/redirect-cors.py`
+      + `?location=${SAME_ORIGIN}/resource-timing/resources/empty.js`
+      + `?pipe=status(${status})`;
+    attribute_test(
+      loader, new URL(destUrl),
+      entry => {
+        assert_equals(entry.responseStatus, status,
+          `response status should be exposed for iframes having only same`
+          + ` origin redirects`);
+      }
+    );
+  }
+};
+</script>
+</body>
+</html>
diff --git a/test/fixtures/wpt/resource-timing/sizes-redirect-img.html b/test/fixtures/wpt/resource-timing/sizes-redirect-img.html
index 786018d0c4634c3..e440029782b5d5e 100644
--- a/test/fixtures/wpt/resource-timing/sizes-redirect-img.html
+++ b/test/fixtures/wpt/resource-timing/sizes-redirect-img.html
@@ -18,7 +18,7 @@
 
 const redirectUrl = (redirectSourceOrigin, targetUrl) => {
   return redirectSourceOrigin +
-    '/resource-timing/resources/redirect-cors.py?timing_allow_origin=*' +
+    '/resource-timing/resources/redirect-cors.py?allow_origin=*&timing_allow_origin=*' +
     '&location=' + encodeURIComponent(targetUrl);
 };
 
@@ -35,18 +35,18 @@
   verify_entry,
   "PerformanceResourceTiming sizes redirect image - same origin redirect");
 
-attribute_test(load.image,
+attribute_test(load.image_cors,
   redirectUrl(hostInfo.HTTP_REMOTE_ORIGIN, baseUrl),
   verify_entry,
   "PerformanceResourceTiming sizes redirect image - cross origin redirect");
 
-attribute_test(load.image,
+attribute_test(load.image_cors,
   redirectUrl(hostInfo.HTTP_REMOTE_ORIGIN,
     redirectUrl(hostInfo.HTTP_ORIGIN, baseUrl)),
   verify_entry,
   "PerformanceResourceTiming sizes redirect image - cross origin to same origin redirect");
 
-attribute_test(load.image,
+attribute_test(load.image_cors,
   redirectUrl(hostInfo.HTTP_ORIGIN,
     redirectUrl(hostInfo.HTTP_REMOTE_ORIGIN,
       redirectUrl(hostInfo.HTTP_ORIGIN,
diff --git a/test/fixtures/wpt/resource-timing/tentative/document-initiated.html b/test/fixtures/wpt/resource-timing/tentative/document-initiated.html
new file mode 100644
index 000000000000000..eea2bb2761d79cb
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/tentative/document-initiated.html
@@ -0,0 +1,78 @@
+<!DOCTYPE html>
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+
+  <!-- Helper Functions for getting ResourceID -->
+  <script src="../resources/get-resourceID.js"></script>
+  <!-- Responsible for testing Initiator Attribute -->
+  <script src="../resources/test-initiator.js"></script>
+
+  <!-- Empty Blocking Script -->
+  <script src="../resources/empty.js?blocking"></script>
+  <!-- Empty Preloaded Script -->
+  <link rel="preload" href="../resources/empty.js?preload" as="script" />
+  <!--  Loading arbitrary Empty Blocking Async Script -->
+  <script async src="../resources/empty.js?async"></script>
+  <!-- Loading arbitrary Empty Deferred Script -->
+  <script defer src="../resources/empty.js?deferred"></script>
+  <!-- Loading arbitrary Empty Module Script -->
+  <script type="module" src="../resources/empty.js?module"></script>
+  <!-- Empty Stylesheet -->
+  <link rel="stylesheet" href="../resources/empty_style.css?link" />
+  <!-- Inline Styles -->
+  <style>
+    body {
+      background-image: url("/images/blue.png?inline-style");
+      font-family: remoteFont, sans-serif;
+    }
+    @font-face {
+      font-family: remoteFont;
+      src: url("/fonts/Ahem.ttf");
+    }
+  </style>
+</head>
+<body>
+  <!-- Loading an arbitrary Image using <img> tag -->
+  <img
+    src="/images/blue.png?using-Img-tag"
+    alt="Sample Image for testing initiator Attribute"
+  />
+
+  <iframe src="../resources/green.html"></iframe>
+
+  <script>
+    // Load arbitrary stylesheet with inline script
+    const link = document.createElement("link");
+    link.rel = "stylesheet";
+    link.href = "../resources/empty_style.css?inline-script";
+    document.head.appendChild(link);
+
+    // Load arbitrary image with inline script
+    const img = document.createElement("img");
+    img.src = "/images/blue.png?inline-script";
+    document.body.appendChild(img);
+
+    // Testing Initiator of all the resources loaded
+    promise_test(async (t) => {
+      const expectedInitiator = await getDocumentResourceID();
+      const resources = [
+        "empty.js?blocking",
+        "empty.js?preload",
+        "empty.js?async",
+        "empty.js?deferred",
+        "empty.js?module",
+        "empty_style.css?link",
+        "blue.png?inline-style",
+        "Ahem.ttf",
+        "blue.png?using-Img-tag",
+        "green.html",
+        "empty_style.css?inline-script",
+        "blue.png?inline-script",
+      ];
+      for (const resource of resources) {
+        await testResourceInitiator(resource, expectedInitiator);
+      }
+    }, "Ensure initiator Attribute matches with Document ResourceID");
+  </script>
+</body>
diff --git a/test/fixtures/wpt/resource-timing/tentative/script-initiated.html b/test/fixtures/wpt/resource-timing/tentative/script-initiated.html
new file mode 100644
index 000000000000000..d6f3d1a32034a7d
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/tentative/script-initiated.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+
+  <!-- Helper Functions for getting ResourceID -->
+  <script src="../resources/get-resourceID.js"></script>
+  <!-- Responsible for testing Initiator Attribute -->
+  <script src="../resources/test-initiator.js"></script>
+
+  <!--Script Responsible for loading various other resources  -->
+  <script src="../resources/loadingResources.js"></script>
+</head>
+<body>
+</body>
+<script>
+  promise_test(async (t) => {
+    const expectedInitiator = await getResourceID("loadingResources.js");
+    const resources = ["empty_style.css", "blue.png", "green.html", "empty.js"];
+    for (const resource of resources) {
+      await testResourceInitiator(resource, expectedInitiator);
+    }
+  }, "Ensure initiator Attribute matches with Script ResourceID");
+</script>
diff --git a/test/fixtures/wpt/resource-timing/tentative/stylesheet-initiated.html b/test/fixtures/wpt/resource-timing/tentative/stylesheet-initiated.html
new file mode 100644
index 000000000000000..d12e3d193d08374
--- /dev/null
+++ b/test/fixtures/wpt/resource-timing/tentative/stylesheet-initiated.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<head>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+
+  <!-- Helper Functions for getting ResourceID -->
+  <script src="../resources/get-resourceID.js"></script>
+  <!-- Responsible for testing Initiator Attribute -->
+  <script src="../resources/test-initiator.js"></script>
+
+  <!-- Stylesheet responsible for fetching other Resources.-->
+  <link rel="stylesheet" href="../resources/nested.css" />
+</head>
+<body></body>
+<script>
+  promise_test(async (t) => {
+    const expectedInitiator = await getResourceID("nested.css");
+    const resources = ["resource_timing_test0.css", "Ahem.ttf", "blue.png"];
+    for (const resource of resources) {
+      await testResourceInitiator(resource, expectedInitiator);
+    }
+  }, "Ensure initiator Attribute matches with Stylesheet ResourceID");
+</script>
diff --git a/test/fixtures/wpt/resource-timing/tojson.html b/test/fixtures/wpt/resource-timing/tojson.html
index 7a6187d3d55bcdf..2564b855dffb8e4 100644
--- a/test/fixtures/wpt/resource-timing/tojson.html
+++ b/test/fixtures/wpt/resource-timing/tojson.html
@@ -47,7 +47,9 @@
         'transferSize',
         'encodedBodySize',
         'decodedBodySize',
-        'renderBlockingStatus'
+        'renderBlockingStatus',
+        'responseStatus',
+        'contentType',
       ];
       for (const key of performanceResourceTimingKeys) {
         try {
diff --git a/test/fixtures/wpt/resources/check-layout-th.js b/test/fixtures/wpt/resources/check-layout-th.js
index f14ca3246b8ea21..54ddb35f3112001 100644
--- a/test/fixtures/wpt/resources/check-layout-th.js
+++ b/test/fixtures/wpt/resources/check-layout-th.js
@@ -218,6 +218,7 @@ window.checkLayout = function(selectorList, callDone = true)
     nodes = Array.prototype.slice.call(nodes);
     var checkedLayout = false;
     Array.prototype.forEach.call(nodes, function(node) {
+        const title = node.title == '' ? '' : `: ${node.title}`;
         test(function(t) {
             var container = node.parentNode.className == 'container' ? node.parentNode : node;
             var prefix =
@@ -240,7 +241,7 @@ window.checkLayout = function(selectorList, callDone = true)
               }
                 checkedLayout |= !passed;
             }
-        }, selectorList + ' ' + String(++testNumber));
+        }, `${selectorList} ${++testNumber}${title}`);
     });
     if (!checkedLayout) {
         console.error("No valid data-* attributes found in selector list : " + selectorList);
diff --git a/test/fixtures/wpt/resources/declarative-shadow-dom-polyfill.js b/test/fixtures/wpt/resources/declarative-shadow-dom-polyfill.js
deleted file mode 100644
index 99a3e911eb63362..000000000000000
--- a/test/fixtures/wpt/resources/declarative-shadow-dom-polyfill.js
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Polyfill for attaching shadow trees for declarative Shadow DOM for
- * implementations that do not support declarative Shadow DOM.
- *
- * Note: this polyfill will feature-detect the native feature, and do nothing
- *       if supported.
- *
- * See: https://github.com/whatwg/html/pull/5465
- *
- * root: The root of the subtree in which to upgrade shadow roots
- *
- */
-
-function polyfill_declarative_shadow_dom(root) {
-  if (HTMLTemplateElement.prototype.hasOwnProperty('shadowRootMode'))
-    return;
-  root.querySelectorAll("template[shadowrootmode]").forEach(template => {
-    const mode = template.getAttribute("shadowrootmode");
-    const delegatesFocus = template.hasAttribute("shadowrootdelegatesfocus");
-    const shadowRoot = template.parentNode.attachShadow({ mode, delegatesFocus });
-    shadowRoot.appendChild(template.content);
-    template.remove();
-    polyfill_declarative_shadow_dom(shadowRoot);
-  });
-}
diff --git a/test/fixtures/wpt/resources/idlharness.js b/test/fixtures/wpt/resources/idlharness.js
index 8f741b09b26bcb5..4cf19234af20eb4 100644
--- a/test/fixtures/wpt/resources/idlharness.js
+++ b/test/fixtures/wpt/resources/idlharness.js
@@ -566,6 +566,7 @@ IdlArray.prototype.is_json_type = function(type)
        case "Uint8ClampedArray":
        case "BigInt64Array":
        case "BigUint64Array":
+       case "Float16Array":
        case "Float32Array":
        case "Float64Array":
        case "ArrayBuffer":
diff --git a/test/fixtures/wpt/resources/testdriver.js b/test/fixtures/wpt/resources/testdriver.js
index ddf723cb3ee8a5b..985dbb0e4030aaa 100644
--- a/test/fixtures/wpt/resources/testdriver.js
+++ b/test/fixtures/wpt/resources/testdriver.js
@@ -49,6 +49,58 @@
      * @namespace {test_driver}
      */
     window.test_driver = {
+        /**
+         Represents `WebDriver BiDi <https://w3c.github.io/webdriver-bidi>`_ protocol.
+         */
+        bidi: {
+            /**
+             * `log <https://w3c.github.io/webdriver-bidi/#module-log>`_ module.
+             */
+            log: {
+                /**
+                 * `log.entryAdded <https://w3c.github.io/webdriver-bidi/#event-log-entryAdded>`_ event.
+                 */
+                entry_added: {
+                    /**
+                     * Subscribe to the `log.entryAdded` event. This does not
+                     * add actual listeners. To listen to the event, use the
+                     * `on` or `once` methods.
+                     * @param {{contexts?: null | (string | Window)[]}} params - Parameters for the subscription.
+                     * * `contexts`: an array of window proxies or browsing
+                     * context ids to listen to the event. If not provided, the
+                     * event subscription is done for the current window's
+                     * browsing context. `null` for the global subscription.
+                     * @return {Promise<void>}
+                     */
+                    subscribe: async function (params = {}) {
+                        return window.test_driver_internal.bidi.log.entry_added.subscribe(params);
+                    },
+                    /**
+                     * Add an event listener for the `log.entryAdded
+                     * <https://w3c.github.io/webdriver-bidi/#event-log-entryAdded>`_ event. Make sure `subscribe` is
+                     * called before using this method.
+                     *
+                     * @param callback {function(event): void} - The callback
+                     * to be called when the event is fired.
+                     * @returns {function(): void} - A function to call to
+                     * remove the event listener.
+                     */
+                    on: function (callback) {
+                        return window.test_driver_internal.bidi.log.entry_added.on(callback);
+                    },
+                    once: function () {
+                        return new Promise(resolve => {
+                            const remove_handler = window.test_driver_internal.bidi.log.entry_added.on(
+                                data => {
+                                    resolve(data);
+                                    remove_handler();
+                                });
+                        });
+                    },
+                }
+            }
+        },
+
         /**
          * Set the context in which testharness.js is loaded
          *
@@ -357,6 +409,25 @@
             return window.test_driver_internal.set_window_rect(rect, context);
         },
 
+        /**
+         * Gets a rect with the size and position on the screen from the current window state.
+         *
+         * Matches the behaviour of the `Get Window Rect
+         * <https://www.w3.org/TR/webdriver/#get-window-rect>`_
+         * WebDriver command
+         *
+         * @param {WindowProxy} context - Browsing context in which
+         *                                to run the call, or null for the current
+         *                                browsing context.
+         *
+         * @returns {Promise} fulfilled after the window rect is returned, or rejected
+         * in cases the WebDriver command returns errors. Returns a
+         * `WindowRect <https://www.w3.org/TR/webdriver/#dfn-windowrect-object>`_
+         */
+        get_window_rect: function(context=null) {
+            return window.test_driver_internal.get_window_rect(context);
+        },
+
         /**
          * Send a sequence of actions
          *
@@ -647,7 +718,7 @@
          *
          * This function places `Secure Payment
          * Confirmation <https://w3c.github.io/secure-payment-confirmation>`_ into
-         * an automated 'autoaccept' or 'autoreject' mode, to allow testing
+         * an automated 'autoAccept' or 'autoReject' mode, to allow testing
          * without user interaction with the transaction UX prompt.
          *
          * Matches the `Set SPC Transaction Mode
@@ -667,8 +738,8 @@
          * @param {String} mode - The `transaction mode
          *                        <https://w3c.github.io/secure-payment-confirmation/#enumdef-transactionautomationmode>`_
          *                        to set. Must be one of "``none``",
-         *                        "``autoaccept``", or
-         *                        "``autoreject``".
+         *                        "``autoAccept``", or
+         *                        "``autoReject``".
          * @param {WindowProxy} context - Browsing context in which
          *                                to run the call, or null for the current
          *                                browsing context.
@@ -680,6 +751,42 @@
           return window.test_driver_internal.set_spc_transaction_mode(mode, context);
         },
 
+        /**
+         * Sets the current registration automation mode for Register Protocol Handlers.
+         *
+         * This function places `Register Protocol Handlers
+         * <https://html.spec.whatwg.org/multipage/system-state.html#custom-handlers>`_ into
+         * an automated 'autoAccept' or 'autoReject' mode, to allow testing
+         * without user interaction with the transaction UX prompt.
+         *
+         * Matches the `Set Register Protocol Handler Mode
+         * <https://html.spec.whatwg.org/multipage/system-state.html#set-rph-registration-mode>`_
+         * WebDriver command.
+         *
+         * @example
+         * await test_driver.set_rph_registration_mode("autoAccept");
+         * test.add_cleanup(() => {
+         *   return test_driver.set_rph_registration_mode("none");
+         * });
+         *
+         * navigator.registerProtocolHandler('web+soup', 'soup?url=%s');
+         *
+         * @param {String} mode - The `registration mode
+         *                        <https://html.spec.whatwg.org/multipage/system-state.html#registerprotocolhandler()-automation-mode>`_
+         *                        to set. Must be one of "``none``",
+         *                        "``autoAccept``", or
+         *                        "``autoReject``".
+         * @param {WindowProxy} context - Browsing context in which
+         *                                to run the call, or null for the current
+         *                                browsing context.
+         *
+         * @returns {Promise} Fulfilled after the transaction mode has been set,
+         *                    or rejected if setting the mode fails.
+         */
+        set_rph_registration_mode: function(mode, context=null) {
+          return window.test_driver_internal.set_rph_registration_mode(mode, context);
+        },
+
         /**
          * Cancels the Federated Credential Management dialog
          *
@@ -968,6 +1075,72 @@
          */
         get_virtual_sensor_information: function(sensor_type, context=null) {
             return window.test_driver_internal.get_virtual_sensor_information(sensor_type, context);
+        },
+
+        /**
+         * Overrides device posture set by hardware.
+         *
+         * Matches the `Set device posture
+         * <https://w3c.github.io/device-posture/#set-device-posture>`_
+         * WebDriver command.
+         *
+         * @param {String} posture - A `DevicePostureType
+         *                           <https://w3c.github.io/device-posture/#dom-deviceposturetype>`_
+         *                           either "continuous" or "folded".
+         * @param {WindowProxy} [context=null] - Browsing context in which to
+         *                                       run the call, or null for the
+         *                                       current browsing context.
+         *
+         * @returns {Promise} Fulfilled when device posture is set.
+         *                    Rejected in case the WebDriver command errors out
+         *                    (including if a device posture of the given type
+         *                    does not exist).
+         */
+        set_device_posture: function(posture, context=null) {
+            return window.test_driver_internal.set_device_posture(posture, context);
+        },
+
+        /**
+         * Removes device posture override and returns device posture control
+         * back to hardware.
+         *
+         * Matches the `Clear device posture
+         * <https://w3c.github.io/device-posture/#clear-device-posture>`_
+         * WebDriver command.
+         *
+         * @param {WindowProxy} [context=null] - Browsing context in which to
+         *                                       run the call, or null for the
+         *                                       current browsing context.
+         *
+         * @returns {Promise} Fulfilled after the device posture override has
+         *                    been removed. Rejected in case the WebDriver
+         *                    command errors out.
+         */
+        clear_device_posture: function(context=null) {
+            return window.test_driver_internal.clear_device_posture(context);
+        },
+
+        /**
+         * Runs the `bounce tracking timer algorithm
+         * <https://privacycg.github.io/nav-tracking-mitigations/#bounce-tracking-timer>`_,
+         * which removes all hosts from the stateful bounce tracking map, without
+         * regard for the bounce tracking grace period and returns a list of the
+         * deleted hosts.
+         *
+         * Matches the `Run Bounce Tracking Mitigations
+         * https://privacycg.github.io/nav-tracking-mitigations/#run-bounce-tracking-mitigations-command`_
+         * WebDriver command.
+         *
+         * @param {WindowProxy} [context=null] - Browsing context in which to
+         *                                       run the call, or null for the
+         *                                       current browsing context.
+         * @returns {Promise} Fulfilled after the bounce tracking timer
+         *                    algorithm has finished running. Returns an array
+         *                    of all hosts that were in the stateful bounce
+         *                    tracking map before deletion occurred.
+         */
+        run_bounce_tracking_mitigations: function (context = null) {
+            return window.test_driver_internal.run_bounce_tracking_mitigations(context);
         }
     };
 
@@ -980,6 +1153,21 @@
          */
         in_automation: false,
 
+        bidi: {
+            log: {
+                entry_added: {
+                    async subscribe() {
+                        throw new Error(
+                            "bidi.log.entry_added.subscribe is not implemented by testdriver-vendor.js");
+                    },
+                    on() {
+                        throw new Error(
+                            "bidi.log.entry_added.on is not implemented by testdriver-vendor.js");
+                    }
+                }
+            }
+        },
+
         async click(element, coords) {
             if (this.in_automation) {
                 throw new Error("click() is not implemented by testdriver-vendor.js");
@@ -1002,6 +1190,14 @@
             throw new Error("get_named_cookie() is not implemented by testdriver-vendor.js");
         },
 
+        async get_computed_role(element) {
+            throw new Error("get_computed_role is a testdriver.js function which cannot be run in this context.");
+        },
+
+        async get_computed_name(element) {
+            throw new Error("get_computed_name is a testdriver.js function which cannot be run in this context.");
+        },
+
         async send_keys(element, keys) {
             if (this.in_automation) {
                 throw new Error("send_keys() is not implemented by testdriver-vendor.js");
@@ -1046,6 +1242,10 @@
             throw new Error("set_window_rect() is not implemented by testdriver-vendor.js");
         },
 
+        async get_window_rect(context=null) {
+            throw new Error("get_window_rect() is not implemented by testdriver-vendor.js");
+        },
+
         async action_sequence(actions, context=null) {
             throw new Error("action_sequence() is not implemented by testdriver-vendor.js");
         },
@@ -1094,6 +1294,10 @@
             throw new Error("set_spc_transaction_mode() is not implemented by testdriver-vendor.js");
         },
 
+        set_rph_registration_mode: function(mode, context=null) {
+            return Promise.reject(new Error("unimplemented"));
+        },
+
         async cancel_fedcm_dialog(context=null) {
             throw new Error("cancel_fedcm_dialog() is not implemented by testdriver-vendor.js");
         },
@@ -1140,6 +1344,18 @@
 
         async get_virtual_sensor_information(sensor_type, context=null) {
             throw new Error("get_virtual_sensor_information() is not implemented by testdriver-vendor.js");
+        },
+
+        async set_device_posture(posture, context=null) {
+            throw new Error("set_device_posture() is not implemented by testdriver-vendor.js");
+        },
+
+        async clear_device_posture(context=null) {
+            throw new Error("clear_device_posture() is not implemented by testdriver-vendor.js");
+        },
+
+        async run_bounce_tracking_mitigations(context=null) {
+            throw new Error("run_bounce_tracking_mitigations() is not implemented by testdriver-vendor.js");
         }
     };
 })();
diff --git a/test/fixtures/wpt/resources/testharness.js b/test/fixtures/wpt/resources/testharness.js
index 497ae23f0e83ee2..7fd5336bf34ae9d 100644
--- a/test/fixtures/wpt/resources/testharness.js
+++ b/test/fixtures/wpt/resources/testharness.js
@@ -91,7 +91,12 @@
         }
 
         on_event(window, 'load', function() {
+          setTimeout(() => {
             this_obj.all_loaded = true;
+            if (tests.all_done()) {
+              tests.complete();
+            }
+          },0);
         });
 
         on_event(window, 'message', function(event) {
@@ -852,7 +857,7 @@
             promise = promiseOrConstructor;
             description = descriptionOrPromise;
             assert(maybeDescription === undefined,
-                   "Too many args pased to no-constructor version of promise_rejects_dom");
+                   "Too many args passed to no-constructor version of promise_rejects_dom, or accidentally explicitly passed undefined");
         }
         return bring_promise_to_current_realm(promise)
             .then(test.unreached_func("Should have rejected: " + description))
@@ -1196,6 +1201,23 @@
         object.addEventListener(event, callback, false);
     }
 
+    // Internal helper function to provide timeout-like functionality in
+    // environments where there is no setTimeout(). (No timeout ID or
+    // clearTimeout().)
+    function fake_set_timeout(callback, delay) {
+        var p = Promise.resolve();
+        var start = Date.now();
+        var end = start + delay;
+        function check() {
+            if ((end - Date.now()) > 0) {
+                p.then(check);
+            } else {
+                callback();
+            }
+        }
+        p.then(check);
+    }
+
     /**
      * Global version of :js:func:`Test.step_timeout` for use in single page tests.
      *
@@ -1207,7 +1229,8 @@
     function step_timeout(func, timeout) {
         var outer_this = this;
         var args = Array.prototype.slice.call(arguments, 2);
-        return setTimeout(function() {
+        var local_set_timeout = typeof global_scope.setTimeout === "undefined" ? fake_set_timeout : setTimeout;
+        return local_set_timeout(function() {
             func.apply(outer_this, args);
         }, timeout * tests.timeout_multiplier);
     }
@@ -2151,7 +2174,7 @@
             func = funcOrConstructor;
             description = descriptionOrFunc;
             assert(maybeDescription === undefined,
-                   "Too many args pased to no-constructor version of assert_throws_dom");
+                   "Too many args passed to no-constructor version of assert_throws_dom, or accidentally explicitly passed undefined");
         }
         assert_throws_dom_impl(type, func, description, "assert_throws_dom", constructor)
     }
@@ -2715,7 +2738,8 @@
     Test.prototype.step_timeout = function(func, timeout) {
         var test_this = this;
         var args = Array.prototype.slice.call(arguments, 2);
-        return setTimeout(this.step_func(function() {
+        var local_set_timeout = typeof global_scope.setTimeout === "undefined" ? fake_set_timeout : setTimeout;
+        return local_set_timeout(this.step_func(function() {
             return func.apply(test_this, args);
         }), timeout * tests.timeout_multiplier);
     };
@@ -2746,6 +2770,7 @@
         var timeout_full = timeout * tests.timeout_multiplier;
         var remaining = Math.ceil(timeout_full / interval);
         var test_this = this;
+        var local_set_timeout = typeof global_scope.setTimeout === 'undefined' ? fake_set_timeout : setTimeout;
 
         const step = test_this.step_func((result) => {
             if (result) {
@@ -2756,7 +2781,7 @@
                            "Timed out waiting on condition");
                 }
                 remaining--;
-                setTimeout(wait_for_inner, interval);
+                local_set_timeout(wait_for_inner, interval);
             }
         });
 
@@ -4169,11 +4194,7 @@
                                                  status
                                                 ],
                                                ],
-                                               ["button",
-                                                {"onclick": "let evt = new Event('__test_restart'); " +
-                                                 "let canceled = !window.dispatchEvent(evt);" +
-                                                 "if (!canceled) { location.reload() }"},
-                                                "Rerun"]
+                                               ["button", {"id":"rerun"}, "Rerun"]
                                               ]];
 
                                     if (harness_status.status === harness_status.ERROR) {
@@ -4205,6 +4226,13 @@
 
         log.appendChild(render(summary_template, {num_tests:tests.length}, output_document));
 
+        output_document.getElementById("rerun").addEventListener("click",
+            function() {
+                let evt = new Event('__test_restart');
+                let canceled = !window.dispatchEvent(evt);
+                if (!canceled) { location.reload(); }
+            });
+
         forEach(output_document.querySelectorAll("section#summary label"),
                 function(element)
                 {
@@ -4229,18 +4257,6 @@
                              });
                 });
 
-        // This use of innerHTML plus manual escaping is not recommended in
-        // general, but is necessary here for performance.  Using textContent
-        // on each individual <td> adds tens of seconds of execution time for
-        // large test suites (tens of thousands of tests).
-        function escape_html(s)
-        {
-            return s.replace(/\&/g, "&amp;")
-                .replace(/</g, "&lt;")
-                .replace(/"/g, "&quot;")
-                .replace(/'/g, "&#39;");
-        }
-
         function has_assertions()
         {
             for (var i = 0; i < tests.length; i++) {
@@ -4271,81 +4287,63 @@
         });
 
         function get_asserts_output(test) {
+            const asserts_output = render(
+                ["details", {},
+                    ["summary", {}, "Asserts run"],
+                    ["table", {}, ""] ]);
+
             var asserts = asserts_run_by_test.get(test);
             if (!asserts) {
-                return "No asserts ran";
+                asserts_output.querySelector("summary").insertAdjacentText("afterend", "No asserts ran");
+                return asserts_output;
             }
-            rv = "<table>";
-            rv += asserts.map(assert => {
-                var output_fn = "<strong>" + escape_html(assert.assert_name) + "</strong>(";
-                var prefix_len = output_fn.length;
-                var output_args = assert.args;
-                var output_len = output_args.reduce((prev, current) => prev+current, prefix_len);
-                if (output_len[output_len.length - 1] > 50) {
-                    output_args = output_args.map((x, i) =>
-                    (i > 0 ? "  ".repeat(prefix_len) : "" )+ x + (i < output_args.length - 1 ? ",\n" : ""));
-                } else {
-                    output_args = output_args.map((x, i) => x + (i < output_args.length - 1 ? ", " : ""));
-                }
-                output_fn += escape_html(output_args.join(""));
-                output_fn += ')';
-                var output_location;
+
+            const table = asserts_output.querySelector("table");
+            for (const assert of asserts) {
+                const status_class_name = status_class(Test.prototype.status_formats[assert.status]);
+                var output_fn = "(" + assert.args.join(", ") + ")";
                 if (assert.stack) {
-                    output_location = assert.stack.split("\n", 1)[0].replace(/@?\w+:\/\/[^ "\/]+(?::\d+)?/g, " ");
+                    output_fn += "\n";
+                    output_fn += assert.stack.split("\n", 1)[0].replace(/@?\w+:\/\/[^ "\/]+(?::\d+)?/g, " ");
                 }
-                return "<tr class='overall-" +
-                    status_class(Test.prototype.status_formats[assert.status]) + "'>" +
-                    "<td class='" +
-                    status_class(Test.prototype.status_formats[assert.status]) + "'>" +
-                    Test.prototype.status_formats[assert.status] + "</td>" +
-                    "<td><pre>" +
-                    output_fn +
-                    (output_location ? "\n" + escape_html(output_location) : "") +
-                    "</pre></td></tr>";
+                table.appendChild(render(
+                    ["tr", {"class":"overall-" + status_class_name},
+                        ["td", {"class":status_class_name}, Test.prototype.status_formats[assert.status]],
+                        ["td", {}, ["pre", {}, ["strong", {}, assert.assert_name], output_fn]] ]));
             }
-            ).join("\n");
-            rv += "</table>";
-            return rv;
+            return asserts_output;
         }
 
-        log.appendChild(document.createElementNS(xhtml_ns, "section"));
         var assertions = has_assertions();
-        var html = "<h2>Details</h2><table id='results' " + (assertions ? "class='assertions'" : "" ) + ">" +
-            "<thead><tr><th>Result</th><th>Test Name</th>" +
-            (assertions ? "<th>Assertion</th>" : "") +
-            "<th>Message</th></tr></thead>" +
-            "<tbody>";
-        for (var i = 0; i < tests.length; i++) {
-            var test = tests[i];
-            html += '<tr class="overall-' +
-                status_class(test.format_status()) +
-                '">' +
-                '<td class="' +
-                status_class(test.format_status()) +
-                '">' +
-                test.format_status() +
-                "</td><td>" +
-                escape_html(test.name) +
-                "</td><td>" +
-                (assertions ? escape_html(get_assertion(test)) + "</td><td>" : "") +
-                escape_html(test.message ? tests[i].message : " ") +
-                (tests[i].stack ? "<pre>" +
-                 escape_html(tests[i].stack) +
-                 "</pre>": "");
+        const section = render(
+            ["section", {},
+                ["h2", {}, "Details"],
+                ["table", {"id":"results", "class":(assertions ? "assertions" : "")},
+                    ["thead", {},
+                        ["tr", {},
+                            ["th", {}, "Result"],
+                            ["th", {}, "Test Name"],
+                            (assertions ? ["th", {}, "Assertion"] : ""),
+                            ["th", {}, "Message" ]]],
+                    ["tbody", {}]]]);
+
+        const tbody = section.querySelector("tbody");
+        for (const test of tests) {
+            const status = test.format_status();
+            const status_class_name = status_class(status);
+            tbody.appendChild(render(
+                ["tr", {"class":"overall-" + status_class_name},
+                    ["td", {"class":status_class_name}, status],
+                    ["td", {}, test.name],
+                    (assertions ? ["td", {}, get_assertion(test)] : ""),
+                    ["td", {},
+                        test.message ?? "",
+                        ["pre", {}, test.stack ?? ""]]]));
             if (!(test instanceof RemoteTest)) {
-                 html += "<details><summary>Asserts run</summary>" + get_asserts_output(test) + "</details>"
+                tbody.lastChild.lastChild.appendChild(get_asserts_output(test));
             }
-            html += "</td></tr>";
-        }
-        html += "</tbody></table>";
-        try {
-            log.lastChild.innerHTML = html;
-        } catch (e) {
-            log.appendChild(document.createElementNS(xhtml_ns, "p"))
-               .textContent = "Setting innerHTML for the log threw an exception.";
-            log.appendChild(document.createElementNS(xhtml_ns, "pre"))
-               .textContent = html;
         }
+        log.appendChild(section);
     };
 
     /*
@@ -4410,13 +4408,20 @@
     {
         var substitution_re = /\$\{([^ }]*)\}/g;
 
-        function do_substitution(input) {
+        function do_substitution(input)
+        {
             var components = input.split(substitution_re);
             var rv = [];
-            for (var i = 0; i < components.length; i += 2) {
-                rv.push(components[i]);
-                if (components[i + 1]) {
-                    rv.push(String(substitutions[components[i + 1]]));
+            if (components.length === 1) {
+                rv = components;
+            } else if (substitutions) {
+                for (var i = 0; i < components.length; i += 2) {
+                    if (components[i]) {
+                        rv.push(components[i]);
+                    }
+                    if (substitutions[components[i + 1]]) {
+                        rv.push(String(substitutions[components[i + 1]]));
+                    }
                 }
             }
             return rv;
@@ -4772,6 +4777,15 @@
         return "Untitled";
     }
 
+    /** Fetches a JSON resource and parses it */
+    async function fetch_json(resource) {
+        const response = await fetch(resource);
+        return await response.json();
+    }
+    if (!global_scope.GLOBAL || !global_scope.GLOBAL.isShadowRealm()) {
+        expose(fetch_json, 'fetch_json');
+    }
+
     /**
      * Setup globals
      */
diff --git a/test/fixtures/wpt/resources/testharnessreport.js b/test/fixtures/wpt/resources/testharnessreport.js
index e5cb40fe0ef652b..405a2d8b06f00fe 100644
--- a/test/fixtures/wpt/resources/testharnessreport.js
+++ b/test/fixtures/wpt/resources/testharnessreport.js
@@ -14,31 +14,6 @@
  * parameters they are called with see testharness.js
  */
 
-function dump_test_results(tests, status) {
-    var results_element = document.createElement("script");
-    results_element.type = "text/json";
-    results_element.id = "__testharness__results__";
-    var test_results = tests.map(function(x) {
-        return {name:x.name, status:x.status, message:x.message, stack:x.stack}
-    });
-    var data = {test:window.location.href,
-                tests:test_results,
-                status: status.status,
-                message: status.message,
-                stack: status.stack};
-    results_element.textContent = JSON.stringify(data);
-
-    // To avoid a HierarchyRequestError with XML documents, ensure that 'results_element'
-    // is inserted at a location that results in a valid document.
-    var parent = document.body
-        ? document.body                 // <body> is required in XHTML documents
-        : document.documentElement;     // fallback for optional <body> in HTML5, SVG, etc.
-
-    parent.appendChild(results_element);
-}
-
-add_completion_callback(dump_test_results);
-
 /* If the parent window has a testharness_properties object,
  * we use this to provide the test settings. This is used by the
  * default in-browser runner to configure the timeout and the
diff --git a/test/fixtures/wpt/streams/transferable/transfer-with-messageport.window.js b/test/fixtures/wpt/streams/transferable/transfer-with-messageport.window.js
index 37f8c9df169607a..3bfe634a6e153d3 100644
--- a/test/fixtures/wpt/streams/transferable/transfer-with-messageport.window.js
+++ b/test/fixtures/wpt/streams/transferable/transfer-with-messageport.window.js
@@ -105,7 +105,7 @@ async function transferMessagePortWith(constructor) {
   await transferMessagePortWithOrder3(new constructor());
 }
 
-async function advancedTransferMesagePortWith(constructor) {
+async function advancedTransferMessagePortWith(constructor) {
   await transferMessagePortWithOrder4(new constructor());
   await transferMessagePortWithOrder5(new constructor());
   await transferMessagePortWithOrder6(new constructor());
@@ -166,7 +166,7 @@ async function mixedTransferMessagePortWithOrder3() {
   );
 }
 
-async function mixedTransferMesagePortWith() {
+async function mixedTransferMessagePortWith() {
   await mixedTransferMessagePortWithOrder1();
   await mixedTransferMessagePortWithOrder2();
   await mixedTransferMessagePortWithOrder3();
@@ -185,19 +185,19 @@ promise_test(async t => {
 }, "Transferring a MessagePort with a TransformStream should set `.ports`");
 
 promise_test(async t => {
-  await transferMessagePortWith(ReadableStream);
+  await advancedTransferMessagePortWith(ReadableStream);
 }, "Transferring a MessagePort with a ReadableStream should set `.ports`, advanced");
 
 promise_test(async t => {
-  await transferMessagePortWith(WritableStream);
+  await advancedTransferMessagePortWith(WritableStream);
 }, "Transferring a MessagePort with a WritableStream should set `.ports`, advanced");
 
 promise_test(async t => {
-  await transferMessagePortWith(TransformStream);
+  await advancedTransferMessagePortWith(TransformStream);
 }, "Transferring a MessagePort with a TransformStream should set `.ports`, advanced");
 
 promise_test(async t => {
-  await mixedTransferMesagePortWith();
+  await mixedTransferMessagePortWith();
 }, "Transferring a MessagePort with multiple streams should set `.ports`");
 
 test(() => {
diff --git a/test/fixtures/wpt/url/META.yml b/test/fixtures/wpt/url/META.yml
index 094b266b64b61b9..415bd0f094c6b9f 100644
--- a/test/fixtures/wpt/url/META.yml
+++ b/test/fixtures/wpt/url/META.yml
@@ -3,5 +3,4 @@ suggested_reviewers:
   - mikewest
   - domenic
   - annevk
-  - GPHemsley
   - TimothyGu
diff --git a/test/fixtures/wpt/url/README.md b/test/fixtures/wpt/url/README.md
index fa5e3b0dc72385a..50227bc4b330ef8 100644
--- a/test/fixtures/wpt/url/README.md
+++ b/test/fixtures/wpt/url/README.md
@@ -1,11 +1,13 @@
-## urltestdata.json
+## urltestdata.json / urltestdata-javascript-only.json
 
-`resources/urltestdata.json` contains URL parsing tests suitable for any URL parser implementation.
+[`resources/urltestdata.json`](resources/urltestdata.json) contains URL parsing tests suitable for any URL parser implementation.
+[`resources/urltestdata-javascript-only.json`](resources/urltestdata-javascript-only.json) contains URL parsing tests specifically meant
+for JavaScript's `URL()` class as well as other languages accepting non-scalar-value strings.
 
-It's used as a source of tests by `a-element.html`, `failure.html`, `url-constructor.any.js`, and
-other test files in this directory.
+These files are used as a source of tests by `a-element.html`, `failure.html`, `url-constructor.any.js`,
+and other test files in this directory.
 
-The format of `resources/urltestdata.json` is a JSON array of comments as strings and test cases as
+Both files share the same format. They consist of a JSON array of comments as strings and test cases as
 objects. The keys for each test case are:
 
 * `input`: a string to be parsed as URL.
diff --git a/test/fixtures/wpt/url/a-element-origin-xhtml.xhtml b/test/fixtures/wpt/url/a-element-origin-xhtml.xhtml
index effcf04bee3fb0d..e68e68dda2ad6cc 100644
--- a/test/fixtures/wpt/url/a-element-origin-xhtml.xhtml
+++ b/test/fixtures/wpt/url/a-element-origin-xhtml.xhtml
@@ -12,4 +12,8 @@
     <script src="resources/a-element-origin.js"></script>
   </body>
 </html>
-<!-- Other dependencies: resources/urltestdata.json -->
+<!--
+  Other dependencies:
+  * resources/urltestdata.json,
+  * resources/urltestdata-javascript-only.json,
+-->
diff --git a/test/fixtures/wpt/url/a-element-origin.html b/test/fixtures/wpt/url/a-element-origin.html
index 9cc8e94cbed0605..7015f853f01a1d3 100644
--- a/test/fixtures/wpt/url/a-element-origin.html
+++ b/test/fixtures/wpt/url/a-element-origin.html
@@ -5,4 +5,8 @@
 <base id=base>
 <div id=log></div>
 <script src=resources/a-element-origin.js></script>
-<!-- Other dependencies: resources/urltestdata.json -->
+<!--
+  Other dependencies:
+  * resources/urltestdata.json,
+  * resources/urltestdata-javascript-only.json,
+-->
diff --git a/test/fixtures/wpt/url/a-element-xhtml.xhtml b/test/fixtures/wpt/url/a-element-xhtml.xhtml
index 05bec4ce4b2f1e5..610481a7819d622 100644
--- a/test/fixtures/wpt/url/a-element-xhtml.xhtml
+++ b/test/fixtures/wpt/url/a-element-xhtml.xhtml
@@ -17,4 +17,8 @@
     <script src="resources/a-element.js"></script>
   </body>
 </html>
-<!-- Other dependencies: resources/urltestdata.json -->
+<!--
+  Other dependencies:
+  * resources/urltestdata.json,
+  * resources/urltestdata-javascript-only.json,
+-->
diff --git a/test/fixtures/wpt/url/a-element.html b/test/fixtures/wpt/url/a-element.html
index 3428fa00574c4d4..a7621d2ded76c4c 100644
--- a/test/fixtures/wpt/url/a-element.html
+++ b/test/fixtures/wpt/url/a-element.html
@@ -10,7 +10,11 @@
 <base id=base>
 <div id=log></div>
 <script src=resources/a-element.js></script>
-<!-- Other dependencies: resources/urltestdata.json -->
+<!--
+  Other dependencies:
+  * resources/urltestdata.json,
+  * resources/urltestdata-javascript-only.json,
+-->
 
 
 <a id="multline-entity" download="multline-entity.txt" href="data:text/plain;charset=utf-8,first%20line&#10;second%20line"> Link with embedded \n is parsed correctly </a>
diff --git a/test/fixtures/wpt/url/failure.html b/test/fixtures/wpt/url/failure.html
index e61f462f97456f3..d95b1d52d672379 100644
--- a/test/fixtures/wpt/url/failure.html
+++ b/test/fixtures/wpt/url/failure.html
@@ -6,7 +6,10 @@
 <script src=/resources/testharnessreport.js></script>
 <div id=log></div>
 <script>
-promise_test(() => fetch("resources/urltestdata.json").then(res => res.json()).then(runTests), "Loading data…")
+promise_test(() => Promise.all([
+  fetch("resources/urltestdata.json").then(res => res.json()),
+  fetch("resources/urltestdata-javascript-only.json").then(res => res.json()),
+]).then((tests) => tests.flat()).then(runTests), "Loading data…");
 
 function runTests(testData) {
   for (const test of testData) {
diff --git a/test/fixtures/wpt/url/resources/a-element-origin.js b/test/fixtures/wpt/url/resources/a-element-origin.js
index c1c24c8986b4aa6..3e5e6cd0c76e43a 100644
--- a/test/fixtures/wpt/url/resources/a-element-origin.js
+++ b/test/fixtures/wpt/url/resources/a-element-origin.js
@@ -1,4 +1,7 @@
-promise_test(() => fetch("resources/urltestdata.json").then(res => res.json()).then(runURLTests), "Loading data…");
+promise_test(() => Promise.all([
+  fetch("resources/urltestdata.json").then(res => res.json()),
+  fetch("resources/urltestdata-javascript-only.json").then(res => res.json()),
+]).then((tests) => tests.flat()).then(runURLTests), "Loading data…");
 
 function setBase(base) {
   document.getElementById("base").href = base
diff --git a/test/fixtures/wpt/url/resources/a-element.js b/test/fixtures/wpt/url/resources/a-element.js
index cff4160d3289423..4a925d9d0e6b2fe 100644
--- a/test/fixtures/wpt/url/resources/a-element.js
+++ b/test/fixtures/wpt/url/resources/a-element.js
@@ -1,4 +1,7 @@
-promise_test(() => fetch("resources/urltestdata.json").then(res => res.json()).then(runURLTests), "Loading data…");
+promise_test(() => Promise.all([
+  fetch("resources/urltestdata.json").then(res => res.json()),
+  fetch("resources/urltestdata-javascript-only.json").then(res => res.json()),
+]).then((tests) => tests.flat()).then(runURLTests), "Loading data…");
 
 function setBase(base) {
   document.getElementById("base").href = base;
diff --git a/test/fixtures/wpt/url/resources/urltestdata-javascript-only.json b/test/fixtures/wpt/url/resources/urltestdata-javascript-only.json
new file mode 100644
index 000000000000000..a3793c1f472f00b
--- /dev/null
+++ b/test/fixtures/wpt/url/resources/urltestdata-javascript-only.json
@@ -0,0 +1,18 @@
+[
+    "See ../README.md for a description of the format.",
+    {
+        "input": "http://example.com/\uD800\uD801\uDFFE\uDFFF\uFDD0\uFDCF\uFDEF\uFDF0\uFFFE\uFFFF?\uD800\uD801\uDFFE\uDFFF\uFDD0\uFDCF\uFDEF\uFDF0\uFFFE\uFFFF",
+        "base": null,
+        "href": "http://example.com/%EF%BF%BD%F0%90%9F%BE%EF%BF%BD%EF%B7%90%EF%B7%8F%EF%B7%AF%EF%B7%B0%EF%BF%BE%EF%BF%BF?%EF%BF%BD%F0%90%9F%BE%EF%BF%BD%EF%B7%90%EF%B7%8F%EF%B7%AF%EF%B7%B0%EF%BF%BE%EF%BF%BF",
+        "origin": "http://example.com",
+        "protocol": "http:",
+        "username": "",
+        "password": "",
+        "host": "example.com",
+        "hostname": "example.com",
+        "port": "",
+        "pathname": "/%EF%BF%BD%F0%90%9F%BE%EF%BF%BD%EF%B7%90%EF%B7%8F%EF%B7%AF%EF%B7%B0%EF%BF%BE%EF%BF%BF",
+        "search": "?%EF%BF%BD%F0%90%9F%BE%EF%BF%BD%EF%B7%90%EF%B7%8F%EF%B7%AF%EF%B7%B0%EF%BF%BE%EF%BF%BF",
+        "hash": ""
+    }
+]
diff --git a/test/fixtures/wpt/url/resources/urltestdata.json b/test/fixtures/wpt/url/resources/urltestdata.json
index 53f6d575e165bf3..91fcca2c3c25570 100644
--- a/test/fixtures/wpt/url/resources/urltestdata.json
+++ b/test/fixtures/wpt/url/resources/urltestdata.json
@@ -4849,21 +4849,6 @@
     "search": "",
     "hash": ""
   },
-  {
-    "input": "http://example.com/\uD800\uD801\uDFFE\uDFFF\uFDD0\uFDCF\uFDEF\uFDF0\uFFFE\uFFFF?\uD800\uD801\uDFFE\uDFFF\uFDD0\uFDCF\uFDEF\uFDF0\uFFFE\uFFFF",
-    "base": null,
-    "href": "http://example.com/%EF%BF%BD%F0%90%9F%BE%EF%BF%BD%EF%B7%90%EF%B7%8F%EF%B7%AF%EF%B7%B0%EF%BF%BE%EF%BF%BF?%EF%BF%BD%F0%90%9F%BE%EF%BF%BD%EF%B7%90%EF%B7%8F%EF%B7%AF%EF%B7%B0%EF%BF%BE%EF%BF%BF",
-    "origin": "http://example.com",
-    "protocol": "http:",
-    "username": "",
-    "password": "",
-    "host": "example.com",
-    "hostname": "example.com",
-    "port": "",
-    "pathname": "/%EF%BF%BD%F0%90%9F%BE%EF%BF%BD%EF%B7%90%EF%B7%8F%EF%B7%AF%EF%B7%B0%EF%BF%BE%EF%BF%BF",
-    "search": "?%EF%BF%BD%F0%90%9F%BE%EF%BF%BD%EF%B7%90%EF%B7%8F%EF%B7%AF%EF%B7%B0%EF%BF%BE%EF%BF%BF",
-    "hash": ""
-  },
   "Forbidden host code points",
   {
     "input": "sc://a\u0000b/",
diff --git a/test/fixtures/wpt/url/url-constructor.any.js b/test/fixtures/wpt/url/url-constructor.any.js
index bea06d025b71882..b4b639b813e9752 100644
--- a/test/fixtures/wpt/url/url-constructor.any.js
+++ b/test/fixtures/wpt/url/url-constructor.any.js
@@ -50,4 +50,7 @@ function runURLTests(urlTests) {
   }
 }
 
-promise_test(() => fetch("resources/urltestdata.json").then(res => res.json()).then(runURLTests), "Loading data…");
+promise_test(() => Promise.all([
+  fetch("resources/urltestdata.json").then(res => res.json()),
+  fetch("resources/urltestdata-javascript-only.json").then(res => res.json()),
+]).then((tests) => tests.flat()).then(runURLTests), "Loading data…");
diff --git a/test/fixtures/wpt/url/url-origin.any.js b/test/fixtures/wpt/url/url-origin.any.js
index 599984c6c17dfe1..b9e0c8585312f6f 100644
--- a/test/fixtures/wpt/url/url-origin.any.js
+++ b/test/fixtures/wpt/url/url-origin.any.js
@@ -1,4 +1,7 @@
-promise_test(() => fetch("resources/urltestdata.json").then(res => res.json()).then(runURLTests), "Loading data…");
+promise_test(() => Promise.all([
+  fetch("resources/urltestdata.json").then(res => res.json()),
+  fetch("resources/urltestdata-javascript-only.json").then(res => res.json()),
+]).then((tests) => tests.flat()).then(runURLTests), "Loading data…");
 
 function runURLTests(urlTests) {
   for (const expected of urlTests) {
diff --git a/test/fixtures/wpt/versions.json b/test/fixtures/wpt/versions.json
index c9320269a28f2a2..45b2ce1a81eedc9 100644
--- a/test/fixtures/wpt/versions.json
+++ b/test/fixtures/wpt/versions.json
@@ -1,22 +1,22 @@
 {
   "common": {
-    "commit": "dbd648158d337580885e70a54f929daf215211a0",
+    "commit": "d8da9d4d1d0dd8525c5dd13623a52b2675529bea",
     "path": "common"
   },
   "compression": {
-    "commit": "5aa50dd4151b5bc1d04d5505366c6e27df30af5b",
+    "commit": "da8d6860b22271d8ef4dc7894509692aaab9adf8",
     "path": "compression"
   },
   "console": {
-    "commit": "767ae354642bee1e4d90b28df4480475b9260e14",
+    "commit": "e48251b77834f9689e9df3f49b93b3387dee72d6",
     "path": "console"
   },
   "dom/abort": {
-    "commit": "d1f1ecbd52f2eab3b7fe5dc1b20b41174f1341ce",
+    "commit": "07a9d09a8fbe95c2c2b439b6a88ef2499543133d",
     "path": "dom/abort"
   },
   "dom/events": {
-    "commit": "ab8999891c6225bef1741c2960033aad620481a8",
+    "commit": "0a811c51619b14f78fec60ba7dd1603795ca6a21",
     "path": "dom/events"
   },
   "encoding": {
@@ -28,11 +28,11 @@
     "path": "fetch/data-urls/resources"
   },
   "FileAPI": {
-    "commit": "cceaf3628da950621004d9b5d8c1d1f367073347",
+    "commit": "1d5fb397da74f1afda7402602fec4255086d7a91",
     "path": "FileAPI"
   },
   "hr-time": {
-    "commit": "34cafd797e58dad280d20040eee012d49ccfa91f",
+    "commit": "614e81711cdf3f3552d8454bd447cd2f0859ae90",
     "path": "hr-time"
   },
   "html/webappapis/atob": {
@@ -40,39 +40,39 @@
     "path": "html/webappapis/atob"
   },
   "html/webappapis/microtask-queuing": {
-    "commit": "2c5c3c4c27d27a419c1fdba3e9879c2d22037074",
+    "commit": "22ecfc9bac05cadf8ed5e47a591f1d7e74fdc2c2",
     "path": "html/webappapis/microtask-queuing"
   },
   "html/webappapis/structured-clone": {
-    "commit": "47d3fb280c9c632e684dee3b78ae1f4c5d5ba640",
+    "commit": "c29dcddf3752377da16049c17ef89e391456bc6e",
     "path": "html/webappapis/structured-clone"
   },
   "html/webappapis/timers": {
-    "commit": "5873f2d8f1f7bbb9c64689e52d04498614632906",
+    "commit": "7a0548ac4799bb8d1eab732be5bd7f5f40e1082c",
     "path": "html/webappapis/timers"
   },
   "interfaces": {
-    "commit": "e90ece61d6e7ff84a0dc9c496588690e6a61cb17",
+    "commit": "ab18bf796b7826552ed35b63594ff7f21e5c537c",
     "path": "interfaces"
   },
   "performance-timeline": {
-    "commit": "17ebc3aea0d6321e69554067c39ab5855e6fb67e",
+    "commit": "94caab7038b27c16d605fa3547dacbee3a2fde4e",
     "path": "performance-timeline"
   },
   "resource-timing": {
-    "commit": "22d38586d04c1d22b64db36f439c6bb84f03db7d",
+    "commit": "95e7763ca921c3e72d38311dc443c9505d6baec9",
     "path": "resource-timing"
   },
   "resources": {
-    "commit": "1e140d63ec885703ce24b3798abd81912696bb85",
+    "commit": "ff5b1bc4dbcb933e6449413ab02ced5d3203b503",
     "path": "resources"
   },
   "streams": {
-    "commit": "2bd26e124cf17b2f0a25c150794d640b07b2a870",
+    "commit": "b5f2d0c48acd328036ac20101458a323cc084de7",
     "path": "streams"
   },
   "url": {
-    "commit": "6a39784534e118acc102cf5252c542378831401d",
+    "commit": "30de0890335d1b5547e25260393668d74755b006",
     "path": "url"
   },
   "user-timing": {
@@ -80,15 +80,15 @@
     "path": "user-timing"
   },
   "wasm/jsapi": {
-    "commit": "cde25e7e3c3b9d2280eb088a3fb9da988793d255",
+    "commit": "140f5c80fd2f1b31fc35026f200175ececbfd2d9",
     "path": "wasm/jsapi"
   },
   "wasm/webapi": {
-    "commit": "fd1b23eeaaf9a01555d4fa29cf79ed11a4c44a50",
+    "commit": "28456b73ca59624420b8ed13469c4bcc9c7a04ca",
     "path": "wasm/webapi"
   },
   "WebCryptoAPI": {
-    "commit": "5e042cbc4ecab7b2279a5fd411c6daa24ca886c6",
+    "commit": "4993c18fa4e51a82e3e2bfbe4f2d223bbb74f4cc",
     "path": "WebCryptoAPI"
   },
   "webidl/ecmascript-binding/es-exceptions": {
@@ -96,11 +96,11 @@
     "path": "webidl/ecmascript-binding/es-exceptions"
   },
   "webmessaging/broadcastchannel": {
-    "commit": "e97fac4791931fb7455ba3fad759d362c7108b09",
+    "commit": "6495c91853a3cf028a401cf4d228fc0b6a5465e4",
     "path": "webmessaging/broadcastchannel"
   },
   "webstorage": {
-    "commit": "9dafa892146c4b5b1f604a39b3cf8677f8f70d44",
+    "commit": "1291340aaaa6e73db43b412e47401eca3830c556",
     "path": "webstorage"
   }
 }
diff --git a/test/fixtures/wpt/wasm/jsapi/assertions.js b/test/fixtures/wpt/wasm/jsapi/assertions.js
index 162f5a9a6b8dcc3..3b370190682a3aa 100644
--- a/test/fixtures/wpt/wasm/jsapi/assertions.js
+++ b/test/fixtures/wpt/wasm/jsapi/assertions.js
@@ -6,6 +6,7 @@ function assert_function_name(fn, name, description) {
   assert_true(propdesc.configurable, "configurable", `${description} name should be configurable`);
   assert_equals(propdesc.value, name, `${description} name should be ${name}`);
 }
+globalThis.assert_function_name = assert_function_name;
 
 function assert_function_length(fn, length, description) {
   const propdesc = Object.getOwnPropertyDescriptor(fn, "length");
@@ -15,6 +16,7 @@ function assert_function_length(fn, length, description) {
   assert_true(propdesc.configurable, "configurable", `${description} length should be configurable`);
   assert_equals(propdesc.value, length, `${description} length should be ${length}`);
 }
+globalThis.assert_function_length = assert_function_length;
 
 function assert_exported_function(fn, { name, length }, description) {
   if (WebAssembly.Function === undefined) {
@@ -28,6 +30,7 @@ function assert_exported_function(fn, { name, length }, description) {
   assert_function_name(fn, name, description);
   assert_function_length(fn, length, description);
 }
+globalThis.assert_exported_function = assert_exported_function;
 
 function assert_Instance(instance, expected_exports) {
   assert_equals(Object.getPrototypeOf(instance), WebAssembly.Instance.prototype,
@@ -77,6 +80,7 @@ function assert_Instance(instance, expected_exports) {
     }
   }
 }
+globalThis.assert_Instance = assert_Instance;
 
 function assert_WebAssemblyInstantiatedSource(actual, expected_exports={}) {
   assert_equals(Object.getPrototypeOf(actual), Object.prototype,
@@ -98,3 +102,4 @@ function assert_WebAssemblyInstantiatedSource(actual, expected_exports={}) {
   assert_true(instance.configurable, "instance: configurable");
   assert_Instance(instance.value, expected_exports);
 }
+globalThis.assert_WebAssemblyInstantiatedSource = assert_WebAssemblyInstantiatedSource;
diff --git a/test/fixtures/wpt/wasm/jsapi/bad-imports.js b/test/fixtures/wpt/wasm/jsapi/bad-imports.js
index 786fc650e326b61..c7c9c6b6cdd1355 100644
--- a/test/fixtures/wpt/wasm/jsapi/bad-imports.js
+++ b/test/fixtures/wpt/wasm/jsapi/bad-imports.js
@@ -183,3 +183,4 @@ function test_bad_imports(t) {
       });
   }
 }
+globalThis.test_bad_imports = test_bad_imports;
diff --git a/test/fixtures/wpt/wasm/jsapi/constructor/compile.any.js b/test/fixtures/wpt/wasm/jsapi/constructor/compile.any.js
index e94ce11717369fb..f822aa30e69eb95 100644
--- a/test/fixtures/wpt/wasm/jsapi/constructor/compile.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/constructor/compile.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 function assert_Module(module) {
diff --git a/test/fixtures/wpt/wasm/jsapi/constructor/instantiate-bad-imports.any.js b/test/fixtures/wpt/wasm/jsapi/constructor/instantiate-bad-imports.any.js
index 30252bd6eeb3ab9..e4926c8d70a86e0 100644
--- a/test/fixtures/wpt/wasm/jsapi/constructor/instantiate-bad-imports.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/constructor/instantiate-bad-imports.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=/wasm/jsapi/bad-imports.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/constructor/instantiate.any.js b/test/fixtures/wpt/wasm/jsapi/constructor/instantiate.any.js
index 8152f3a56f3f439..34e005c4700932b 100644
--- a/test/fixtures/wpt/wasm/jsapi/constructor/instantiate.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/constructor/instantiate.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/instanceTestFactory.js
diff --git a/test/fixtures/wpt/wasm/jsapi/constructor/multi-value.any.js b/test/fixtures/wpt/wasm/jsapi/constructor/multi-value.any.js
index 4b06d1da3c49b93..8786f9b953ba18b 100644
--- a/test/fixtures/wpt/wasm/jsapi/constructor/multi-value.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/constructor/multi-value.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=/wasm/jsapi/assertions.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/constructor/toStringTag.any.js b/test/fixtures/wpt/wasm/jsapi/constructor/toStringTag.any.js
index c6d2cdaf662e8b9..5fae8304f8c0f60 100644
--- a/test/fixtures/wpt/wasm/jsapi/constructor/toStringTag.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/constructor/toStringTag.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 
 "use strict";
 // https://webidl.spec.whatwg.org/#es-namespaces
diff --git a/test/fixtures/wpt/wasm/jsapi/constructor/validate.any.js b/test/fixtures/wpt/wasm/jsapi/constructor/validate.any.js
index 8b4f4582ab29877..fce43d1e175f489 100644
--- a/test/fixtures/wpt/wasm/jsapi/constructor/validate.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/constructor/validate.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 let emptyModuleBinary;
diff --git a/test/fixtures/wpt/wasm/jsapi/exception/basic.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/exception/basic.tentative.any.js
index acf644f904f53d5..cacce99d9cb2270 100644
--- a/test/fixtures/wpt/wasm/jsapi/exception/basic.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/exception/basic.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,worker,jsshell
+// META: global=window,worker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 function assert_throws_wasm(fn, message) {
@@ -11,8 +11,7 @@ function assert_throws_wasm(fn, message) {
 }
 
 promise_test(async () => {
-  const kWasmAnyRef = 0x6f;
-  const kSig_v_r = makeSig([kWasmAnyRef], []);
+  const kSig_v_r = makeSig([kWasmExternRef], []);
   const builder = new WasmModuleBuilder();
   const tagIndex = builder.addTag(kSig_v_r);
   builder.addFunction("throw_param", kSig_v_r)
@@ -48,7 +47,7 @@ promise_test(async () => {
   const tagIndex = builder.addTag(kSig_v_a);
   builder.addFunction("throw_null", kSig_v_v)
     .addBody([
-      kExprRefNull, kWasmAnyFunc,
+      kExprRefNull, kAnyFuncCode,
       kExprThrow, tagIndex,
     ])
     .exportFunc();
@@ -82,7 +81,7 @@ promise_test(async () => {
       kExprCatch, tagIndex,
         kExprReturn,
       kExprEnd,
-      kExprRefNull, kWasmAnyRef,
+      kExprRefNull, kExternRefCode,
     ])
     .exportFunc();
 
@@ -106,7 +105,7 @@ promise_test(async () => {
       kExprCatchAll,
         kExprRethrow, 0x00,
       kExprEnd,
-      kExprRefNull, kWasmAnyRef,
+      kExprRefNull, kExternRefCode,
     ])
     .exportFunc();
 
diff --git a/test/fixtures/wpt/wasm/jsapi/exception/constructor.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/exception/constructor.tentative.any.js
index 7ad08e1883ba13c..a46d1816c351d2e 100644
--- a/test/fixtures/wpt/wasm/jsapi/exception/constructor.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/exception/constructor.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 test(() => {
diff --git a/test/fixtures/wpt/wasm/jsapi/exception/getArg.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/exception/getArg.tentative.any.js
index f0a568a857f0e73..87719c7ebdfb85c 100644
--- a/test/fixtures/wpt/wasm/jsapi/exception/getArg.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/exception/getArg.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/memory/assertions.js
 
 test(() => {
diff --git a/test/fixtures/wpt/wasm/jsapi/exception/identity.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/exception/identity.tentative.any.js
index 65787c107e3c29f..2675668ec73a954 100644
--- a/test/fixtures/wpt/wasm/jsapi/exception/identity.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/exception/identity.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/exception/is.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/exception/is.tentative.any.js
index e28a88a3c5fdcfa..840d00bf0d47a91 100644
--- a/test/fixtures/wpt/wasm/jsapi/exception/is.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/exception/is.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/memory/assertions.js
 
 test(() => {
diff --git a/test/fixtures/wpt/wasm/jsapi/exception/toString.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/exception/toString.tentative.any.js
index 00e801a6fc1a4a2..6885cf0deb6918c 100644
--- a/test/fixtures/wpt/wasm/jsapi/exception/toString.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/exception/toString.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 
 test(() => {
   const argument = { parameters: [] };
diff --git a/test/fixtures/wpt/wasm/jsapi/function/call.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/function/call.tentative.any.js
index 626cd13c9f00954..2e63d5fa103fd17 100644
--- a/test/fixtures/wpt/wasm/jsapi/function/call.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/function/call.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function addxy(x, y) {
diff --git a/test/fixtures/wpt/wasm/jsapi/function/constructor.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/function/constructor.tentative.any.js
index 636aeca4dc1fa01..fc92fcfaf0cf497 100644
--- a/test/fixtures/wpt/wasm/jsapi/function/constructor.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/function/constructor.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function addxy(x, y) {
diff --git a/test/fixtures/wpt/wasm/jsapi/function/table.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/function/table.tentative.any.js
index d7d0d86e3b6a88b..f0dd6ea6f8589a0 100644
--- a/test/fixtures/wpt/wasm/jsapi/function/table.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/function/table.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function testfunc(n) {}
diff --git a/test/fixtures/wpt/wasm/jsapi/function/type.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/function/type.tentative.any.js
index e01a23a9e4339e5..72a7f1bfbe5e0a9 100644
--- a/test/fixtures/wpt/wasm/jsapi/function/type.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/function/type.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function addNumbers(x, y, z) {
diff --git a/test/fixtures/wpt/wasm/jsapi/gc/casts.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/gc/casts.tentative.any.js
new file mode 100644
index 000000000000000..cce06224fd40c70
--- /dev/null
+++ b/test/fixtures/wpt/wasm/jsapi/gc/casts.tentative.any.js
@@ -0,0 +1,332 @@
+// META: global=window,dedicatedworker,jsshell
+// META: script=/wasm/jsapi/wasm-module-builder.js
+
+let exports = {};
+setup(() => {
+  const builder = new WasmModuleBuilder();
+  const structIndex = builder.addStruct([makeField(kWasmI32, true)]);
+  const arrayIndex = builder.addArray(kWasmI32, true);
+  const structIndex2 = builder.addStruct([makeField(kWasmF32, true)]);
+  const arrayIndex2 = builder.addArray(kWasmF32, true);
+  const funcIndex = builder.addType({ params: [], results: [] });
+  const funcIndex2 = builder.addType({ params: [], results: [kWasmI32] });
+
+  const argFunctions = [
+    { name: "any", code: kWasmAnyRef },
+    { name: "eq", code: kWasmEqRef },
+    { name: "struct", code: kWasmStructRef },
+    { name: "array", code: kWasmArrayRef },
+    { name: "i31", code: kWasmI31Ref },
+    { name: "func", code: kWasmFuncRef },
+    { name: "extern", code: kWasmExternRef },
+    { name: "none", code: kWasmNullRef },
+    { name: "nofunc", code: kWasmNullFuncRef },
+    { name: "noextern", code: kWasmNullExternRef },
+    { name: "concreteStruct", code: structIndex },
+    { name: "concreteArray", code: arrayIndex },
+    { name: "concreteFunc", code: funcIndex },
+  ];
+
+  for (const desc of argFunctions) {
+    builder
+      .addFunction(desc.name + "Arg", makeSig_v_x(wasmRefType(desc.code)))
+      .addBody([])
+      .exportFunc();
+
+    builder
+      .addFunction(desc.name + "NullableArg", makeSig_v_x(wasmRefNullType(desc.code)))
+      .addBody([])
+      .exportFunc();
+  }
+
+  builder
+    .addFunction("makeStruct", makeSig_r_v(wasmRefType(structIndex)))
+    .addBody([...wasmI32Const(42),
+              ...GCInstr(kExprStructNew), structIndex])
+    .exportFunc();
+
+  builder
+    .addFunction("makeArray", makeSig_r_v(wasmRefType(arrayIndex)))
+    .addBody([...wasmI32Const(5), ...wasmI32Const(42),
+              ...GCInstr(kExprArrayNew), arrayIndex])
+    .exportFunc();
+
+  builder
+    .addFunction("makeStruct2", makeSig_r_v(wasmRefType(structIndex2)))
+    .addBody([...wasmF32Const(42),
+              ...GCInstr(kExprStructNew), structIndex2])
+    .exportFunc();
+
+  builder
+    .addFunction("makeArray2", makeSig_r_v(wasmRefType(arrayIndex2)))
+    .addBody([...wasmF32Const(42), ...wasmI32Const(5),
+              ...GCInstr(kExprArrayNew), arrayIndex2])
+    .exportFunc();
+
+  builder
+    .addFunction("testFunc", funcIndex)
+    .addBody([])
+    .exportFunc();
+
+  builder
+    .addFunction("testFunc2", funcIndex2)
+    .addBody([...wasmI32Const(42)])
+    .exportFunc();
+
+  const buffer = builder.toBuffer();
+  const module = new WebAssembly.Module(buffer);
+  const instance = new WebAssembly.Instance(module, {});
+  exports = instance.exports;
+});
+
+test(() => {
+  exports.anyArg(exports.makeStruct());
+  exports.anyArg(exports.makeArray());
+  exports.anyArg(42);
+  exports.anyArg(42n);
+  exports.anyArg("foo");
+  exports.anyArg({});
+  exports.anyArg(() => {});
+  exports.anyArg(exports.testFunc);
+  assert_throws_js(TypeError, () => exports.anyArg(null));
+
+  exports.anyNullableArg(null);
+  exports.anyNullableArg(exports.makeStruct());
+  exports.anyNullableArg(exports.makeArray());
+  exports.anyNullableArg(42);
+  exports.anyNullableArg(42n);
+  exports.anyNullableArg("foo");
+  exports.anyNullableArg({});
+  exports.anyNullableArg(() => {});
+  exports.anyNullableArg(exports.testFunc);
+}, "anyref casts");
+
+test(() => {
+  exports.eqArg(exports.makeStruct());
+  exports.eqArg(exports.makeArray());
+  exports.eqArg(42);
+  assert_throws_js(TypeError, () => exports.eqArg(42n));
+  assert_throws_js(TypeError, () => exports.eqArg("foo"));
+  assert_throws_js(TypeError, () => exports.eqArg({}));
+  assert_throws_js(TypeError, () => exports.eqArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.eqArg(() => {}));
+  assert_throws_js(TypeError, () => exports.eqArg(null));
+
+  exports.eqNullableArg(null);
+  exports.eqNullableArg(exports.makeStruct());
+  exports.eqNullableArg(exports.makeArray());
+  exports.eqNullableArg(42);
+  assert_throws_js(TypeError, () => exports.eqNullableArg(42n));
+  assert_throws_js(TypeError, () => exports.eqNullableArg("foo"));
+  assert_throws_js(TypeError, () => exports.eqNullableArg({}));
+  assert_throws_js(TypeError, () => exports.eqNullableArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.eqNullableArg(() => {}));
+}, "eqref casts");
+
+test(() => {
+  exports.structArg(exports.makeStruct());
+  assert_throws_js(TypeError, () => exports.structArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.structArg(42));
+  assert_throws_js(TypeError, () => exports.structArg(42n));
+  assert_throws_js(TypeError, () => exports.structArg("foo"));
+  assert_throws_js(TypeError, () => exports.structArg({}));
+  assert_throws_js(TypeError, () => exports.structArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.structArg(() => {}));
+  assert_throws_js(TypeError, () => exports.structArg(null));
+
+  exports.structNullableArg(null);
+  exports.structNullableArg(exports.makeStruct());
+  assert_throws_js(TypeError, () => exports.structNullableArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.structNullableArg(42));
+  assert_throws_js(TypeError, () => exports.structNullableArg(42n));
+  assert_throws_js(TypeError, () => exports.structNullableArg("foo"));
+  assert_throws_js(TypeError, () => exports.structNullableArg({}));
+  assert_throws_js(TypeError, () => exports.structNullableArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.structNullableArg(() => {}));
+}, "structref casts");
+
+test(() => {
+  exports.arrayArg(exports.makeArray());
+  assert_throws_js(TypeError, () => exports.arrayArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.arrayArg(42));
+  assert_throws_js(TypeError, () => exports.arrayArg(42n));
+  assert_throws_js(TypeError, () => exports.arrayArg("foo"));
+  assert_throws_js(TypeError, () => exports.arrayArg({}));
+  assert_throws_js(TypeError, () => exports.arrayArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.arrayArg(() => {}));
+  assert_throws_js(TypeError, () => exports.arrayArg(null));
+
+  exports.arrayNullableArg(null);
+  exports.arrayNullableArg(exports.makeArray());
+  assert_throws_js(TypeError, () => exports.arrayNullableArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.arrayNullableArg(42));
+  assert_throws_js(TypeError, () => exports.arrayNullableArg(42n));
+  assert_throws_js(TypeError, () => exports.arrayNullableArg("foo"));
+  assert_throws_js(TypeError, () => exports.arrayNullableArg({}));
+  assert_throws_js(TypeError, () => exports.arrayNullableArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.arrayNullableArg(() => {}));
+}, "arrayref casts");
+
+test(() => {
+  exports.i31Arg(42);
+  assert_throws_js(TypeError, () => exports.i31Arg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.i31Arg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.i31Arg(42n));
+  assert_throws_js(TypeError, () => exports.i31Arg("foo"));
+  assert_throws_js(TypeError, () => exports.i31Arg({}));
+  assert_throws_js(TypeError, () => exports.i31Arg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.i31Arg(() => {}));
+  assert_throws_js(TypeError, () => exports.i31Arg(null));
+
+  exports.i31NullableArg(null);
+  exports.i31NullableArg(42);
+  assert_throws_js(TypeError, () => exports.i31NullableArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.i31NullableArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.i31NullableArg(42n));
+  assert_throws_js(TypeError, () => exports.i31NullableArg("foo"));
+  assert_throws_js(TypeError, () => exports.i31NullableArg({}));
+  assert_throws_js(TypeError, () => exports.i31NullableArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.i31NullableArg(() => {}));
+}, "i31ref casts");
+
+test(() => {
+  exports.funcArg(exports.testFunc);
+  assert_throws_js(TypeError, () => exports.funcArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.funcArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.funcArg(42));
+  assert_throws_js(TypeError, () => exports.funcArg(42n));
+  assert_throws_js(TypeError, () => exports.funcArg("foo"));
+  assert_throws_js(TypeError, () => exports.funcArg({}));
+  assert_throws_js(TypeError, () => exports.funcArg(() => {}));
+  assert_throws_js(TypeError, () => exports.funcArg(null));
+
+  exports.funcNullableArg(null);
+  exports.funcNullableArg(exports.testFunc);
+  assert_throws_js(TypeError, () => exports.funcNullableArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.funcNullableArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.funcNullableArg(42));
+  assert_throws_js(TypeError, () => exports.funcNullableArg(42n));
+  assert_throws_js(TypeError, () => exports.funcNullableArg("foo"));
+  assert_throws_js(TypeError, () => exports.funcNullableArg({}));
+  assert_throws_js(TypeError, () => exports.funcNullableArg(() => {}));
+}, "funcref casts");
+
+test(() => {
+  exports.externArg(exports.makeArray());
+  exports.externArg(exports.makeStruct());
+  exports.externArg(42);
+  exports.externArg(42n);
+  exports.externArg("foo");
+  exports.externArg({});
+  exports.externArg(exports.testFunc);
+  exports.externArg(() => {});
+  assert_throws_js(TypeError, () => exports.externArg(null));
+
+  exports.externNullableArg(null);
+  exports.externNullableArg(exports.makeArray());
+  exports.externNullableArg(exports.makeStruct());
+  exports.externNullableArg(42);
+  exports.externNullableArg(42n);
+  exports.externNullableArg("foo");
+  exports.externNullableArg({});
+  exports.externNullableArg(exports.testFunc);
+  exports.externNullableArg(() => {});
+}, "externref casts");
+
+test(() => {
+  for (const nullfunc of [exports.noneArg, exports.nofuncArg, exports.noexternArg]) {
+    assert_throws_js(TypeError, () => nullfunc(exports.makeStruct()));
+    assert_throws_js(TypeError, () => nullfunc(exports.makeArray()));
+    assert_throws_js(TypeError, () => nullfunc(42));
+    assert_throws_js(TypeError, () => nullfunc(42n));
+    assert_throws_js(TypeError, () => nullfunc("foo"));
+    assert_throws_js(TypeError, () => nullfunc({}));
+    assert_throws_js(TypeError, () => nullfunc(exports.testFunc));
+    assert_throws_js(TypeError, () => nullfunc(() => {}));
+    assert_throws_js(TypeError, () => nullfunc(null));
+  }
+
+  for (const nullfunc of [exports.noneNullableArg, exports.nofuncNullableArg, exports.noexternNullableArg]) {
+    nullfunc(null);
+    assert_throws_js(TypeError, () => nullfunc(exports.makeStruct()));
+    assert_throws_js(TypeError, () => nullfunc(exports.makeArray()));
+    assert_throws_js(TypeError, () => nullfunc(42));
+    assert_throws_js(TypeError, () => nullfunc(42n));
+    assert_throws_js(TypeError, () => nullfunc("foo"));
+    assert_throws_js(TypeError, () => nullfunc({}));
+    assert_throws_js(TypeError, () => nullfunc(exports.testFunc));
+    assert_throws_js(TypeError, () => nullfunc(() => {}));
+  }
+}, "null casts");
+
+test(() => {
+  exports.concreteStructArg(exports.makeStruct());
+  assert_throws_js(TypeError, () => exports.concreteStructArg(exports.makeStruct2()));
+  assert_throws_js(TypeError, () => exports.concreteStructArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.concreteStructArg(42));
+  assert_throws_js(TypeError, () => exports.concreteStructArg(42n));
+  assert_throws_js(TypeError, () => exports.concreteStructArg("foo"));
+  assert_throws_js(TypeError, () => exports.concreteStructArg({}));
+  assert_throws_js(TypeError, () => exports.concreteStructArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.concreteStructArg(() => {}));
+  assert_throws_js(TypeError, () => exports.concreteStructArg(null));
+
+  exports.concreteStructNullableArg(null);
+  exports.concreteStructNullableArg(exports.makeStruct());
+  assert_throws_js(TypeError, () => exports.concreteStructNullableArg(exports.makeStruct2()));
+  assert_throws_js(TypeError, () => exports.concreteStructNullableArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.concreteStructNullableArg(42));
+  assert_throws_js(TypeError, () => exports.concreteStructNullableArg(42n));
+  assert_throws_js(TypeError, () => exports.concreteStructNullableArg("foo"));
+  assert_throws_js(TypeError, () => exports.concreteStructNullableArg({}));
+  assert_throws_js(TypeError, () => exports.concreteStructNullableArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.concreteStructNullableArg(() => {}));
+}, "concrete struct casts");
+
+test(() => {
+  exports.concreteArrayArg(exports.makeArray());
+  assert_throws_js(TypeError, () => exports.concreteArrayArg(exports.makeArray2()));
+  assert_throws_js(TypeError, () => exports.concreteArrayArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.concreteArrayArg(42));
+  assert_throws_js(TypeError, () => exports.concreteArrayArg(42n));
+  assert_throws_js(TypeError, () => exports.concreteArrayArg("foo"));
+  assert_throws_js(TypeError, () => exports.concreteArrayArg({}));
+  assert_throws_js(TypeError, () => exports.concreteArrayArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.concreteArrayArg(() => {}));
+  assert_throws_js(TypeError, () => exports.concreteArrayArg(null));
+
+  exports.concreteArrayNullableArg(null);
+  exports.concreteArrayNullableArg(exports.makeArray());
+  assert_throws_js(TypeError, () => exports.concreteArrayNullableArg(exports.makeArray2()));
+  assert_throws_js(TypeError, () => exports.concreteArrayNullableArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.concreteArrayNullableArg(42));
+  assert_throws_js(TypeError, () => exports.concreteArrayNullableArg(42n));
+  assert_throws_js(TypeError, () => exports.concreteArrayNullableArg("foo"));
+  assert_throws_js(TypeError, () => exports.concreteArrayNullableArg({}));
+  assert_throws_js(TypeError, () => exports.concreteArrayNullableArg(exports.testFunc));
+  assert_throws_js(TypeError, () => exports.concreteArrayNullableArg(() => {}));
+}, "concrete array casts");
+
+test(() => {
+  exports.concreteFuncArg(exports.testFunc);
+  assert_throws_js(TypeError, () => exports.concreteFuncArg(exports.testFunc2));
+  assert_throws_js(TypeError, () => exports.concreteFuncArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.concreteFuncArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.concreteFuncArg(42));
+  assert_throws_js(TypeError, () => exports.concreteFuncArg(42n));
+  assert_throws_js(TypeError, () => exports.concreteFuncArg("foo"));
+  assert_throws_js(TypeError, () => exports.concreteFuncArg({}));
+  assert_throws_js(TypeError, () => exports.concreteFuncArg(() => {}));
+  assert_throws_js(TypeError, () => exports.concreteFuncArg(null));
+
+  exports.concreteFuncNullableArg(null);
+  exports.concreteFuncNullableArg(exports.testFunc);
+  assert_throws_js(TypeError, () => exports.concreteFuncNullableArg(exports.testFunc2));
+  assert_throws_js(TypeError, () => exports.concreteFuncNullableArg(exports.makeArray()));
+  assert_throws_js(TypeError, () => exports.concreteFuncNullableArg(exports.makeStruct()));
+  assert_throws_js(TypeError, () => exports.concreteFuncNullableArg(42));
+  assert_throws_js(TypeError, () => exports.concreteFuncNullableArg(42n));
+  assert_throws_js(TypeError, () => exports.concreteFuncNullableArg("foo"));
+  assert_throws_js(TypeError, () => exports.concreteFuncNullableArg({}));
+  assert_throws_js(TypeError, () => exports.concreteFuncNullableArg(() => {}));
+}, "concrete func casts");
diff --git a/test/fixtures/wpt/wasm/jsapi/gc/exported-object.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/gc/exported-object.tentative.any.js
new file mode 100644
index 000000000000000..b572f140067fda6
--- /dev/null
+++ b/test/fixtures/wpt/wasm/jsapi/gc/exported-object.tentative.any.js
@@ -0,0 +1,190 @@
+// META: global=window,dedicatedworker,jsshell
+// META: script=/wasm/jsapi/wasm-module-builder.js
+
+let functions = {};
+setup(() => {
+  const builder = new WasmModuleBuilder();
+
+  const structIndex = builder.addStruct([makeField(kWasmI32, true)]);
+  const arrayIndex = builder.addArray(kWasmI32, true);
+  const structRef = wasmRefType(structIndex);
+  const arrayRef = wasmRefType(arrayIndex);
+
+  builder
+    .addFunction("makeStruct", makeSig_r_v(structRef))
+    .addBody([...wasmI32Const(42),
+              ...GCInstr(kExprStructNew), structIndex])
+    .exportFunc();
+
+  builder
+    .addFunction("makeArray", makeSig_r_v(arrayRef))
+    .addBody([...wasmI32Const(5), ...wasmI32Const(42),
+              ...GCInstr(kExprArrayNew), arrayIndex])
+    .exportFunc();
+
+  const buffer = builder.toBuffer();
+  const module = new WebAssembly.Module(buffer);
+  const instance = new WebAssembly.Instance(module, {});
+  functions = instance.exports;
+});
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_equals(struct.foo, undefined);
+  assert_equals(struct[0], undefined);
+  assert_equals(array.foo, undefined);
+  assert_equals(array[0], undefined);
+}, "property access");
+
+test(() => {
+  "use strict";
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => { struct.foo = 5; });
+  assert_throws_js(TypeError, () => { array.foo = 5; });
+  assert_throws_js(TypeError, () => { struct[0] = 5; });
+  assert_throws_js(TypeError, () => { array[0] = 5; });
+}, "property assignment (strict mode)");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => { struct.foo = 5; });
+  assert_throws_js(TypeError, () => { array.foo = 5; });
+  assert_throws_js(TypeError, () => { struct[0] = 5; });
+  assert_throws_js(TypeError, () => { array[0] = 5; });
+}, "property assignment (non-strict mode)");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_equals(Object.getOwnPropertyNames(struct).length, 0);
+  assert_equals(Object.getOwnPropertyNames(array).length, 0);
+}, "ownPropertyNames");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => Object.defineProperty(struct, "foo", { value: 1 }));
+  assert_throws_js(TypeError, () => Object.defineProperty(array, "foo", { value: 1 }));
+}, "defineProperty");
+
+test(() => {
+  "use strict";
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => delete struct.foo);
+  assert_throws_js(TypeError, () => delete struct[0]);
+  assert_throws_js(TypeError, () => delete array.foo);
+  assert_throws_js(TypeError, () => delete array[0]);
+}, "delete (strict mode)");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => delete struct.foo);
+  assert_throws_js(TypeError, () => delete struct[0]);
+  assert_throws_js(TypeError, () => delete array.foo);
+  assert_throws_js(TypeError, () => delete array[0]);
+}, "delete (non-strict mode)");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_equals(Object.getPrototypeOf(struct), null);
+  assert_equals(Object.getPrototypeOf(array), null);
+}, "getPrototypeOf");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => Object.setPrototypeOf(struct, {}));
+  assert_throws_js(TypeError, () => Object.setPrototypeOf(array, {}));
+}, "setPrototypeOf");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_false(Object.isExtensible(struct));
+  assert_false(Object.isExtensible(array));
+}, "isExtensible");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => Object.preventExtensions(struct));
+  assert_throws_js(TypeError, () => Object.preventExtensions(array));
+}, "preventExtensions");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => Object.seal(struct));
+  assert_throws_js(TypeError, () => Object.seal(array));
+}, "sealing");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_equals(typeof struct, "object");
+  assert_equals(typeof array, "object");
+}, "typeof");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => struct.toString());
+  assert_equals(Object.prototype.toString.call(struct), "[object Object]");
+  assert_throws_js(TypeError, () => array.toString());
+  assert_equals(Object.prototype.toString.call(array), "[object Object]");
+}, "toString");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  assert_throws_js(TypeError, () => struct.valueOf());
+  assert_equals(Object.prototype.valueOf.call(struct), struct);
+  assert_throws_js(TypeError, () => array.valueOf());
+  assert_equals(Object.prototype.valueOf.call(array), array);
+}, "valueOf");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  const map = new Map();
+  map.set(struct, "struct");
+  map.set(array, "array");
+  assert_equals(map.get(struct), "struct");
+  assert_equals(map.get(array), "array");
+}, "GC objects as map keys");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  const set = new Set();
+  set.add(struct);
+  set.add(array);
+  assert_true(set.has(struct));
+  assert_true(set.has(array));
+}, "GC objects as set element");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  const map = new WeakMap();
+  map.set(struct, "struct");
+  map.set(array, "array");
+  assert_equals(map.get(struct), "struct");
+  assert_equals(map.get(array), "array");
+}, "GC objects as weak map keys");
+
+test(() => {
+  const struct = functions.makeStruct();
+  const array = functions.makeArray();
+  const set = new WeakSet();
+  set.add(struct);
+  set.add(array);
+  assert_true(set.has(struct));
+  assert_true(set.has(array));
+}, "GC objects as weak set element");
diff --git a/test/fixtures/wpt/wasm/jsapi/gc/i31.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/gc/i31.tentative.any.js
new file mode 100644
index 000000000000000..17fd82440cc8b29
--- /dev/null
+++ b/test/fixtures/wpt/wasm/jsapi/gc/i31.tentative.any.js
@@ -0,0 +1,98 @@
+// META: global=window,dedicatedworker,jsshell
+// META: script=/wasm/jsapi/wasm-module-builder.js
+
+let exports = {};
+setup(() => {
+  const builder = new WasmModuleBuilder();
+  const i31Ref = wasmRefType(kWasmI31Ref);
+  const i31NullableRef = wasmRefNullType(kWasmI31Ref);
+  const anyRef = wasmRefType(kWasmAnyRef);
+
+  builder
+    .addFunction("makeI31", makeSig_r_x(i31Ref, kWasmI32))
+    .addBody([kExprLocalGet, 0,
+              ...GCInstr(kExprI31New)])
+    .exportFunc();
+
+  builder
+    .addFunction("castI31", makeSig_r_x(kWasmI32, anyRef))
+    .addBody([kExprLocalGet, 0,
+              ...GCInstr(kExprRefCast), kI31RefCode,
+              ...GCInstr(kExprI31GetU)])
+    .exportFunc();
+
+  builder
+    .addFunction("getI31", makeSig_r_x(kWasmI32, i31Ref))
+    .addBody([kExprLocalGet, 0,
+              ...GCInstr(kExprI31GetS)])
+    .exportFunc();
+
+  builder
+    .addFunction("argI31", makeSig_v_x(i31NullableRef))
+    .addBody([])
+    .exportFunc();
+
+  builder
+    .addGlobal(i31NullableRef, true, [...wasmI32Const(0), ...GCInstr(kExprI31New)])
+  builder
+    .addExportOfKind("i31Global", kExternalGlobal, 0);
+
+  builder
+    .addTable(i31NullableRef, 10)
+  builder
+    .addExportOfKind("i31Table", kExternalTable, 0);
+
+  const buffer = builder.toBuffer();
+  const module = new WebAssembly.Module(buffer);
+  const instance = new WebAssembly.Instance(module, {});
+  exports = instance.exports;
+});
+
+test(() => {
+  assert_equals(exports.makeI31(42), 42);
+  assert_equals(exports.makeI31(2 ** 30 - 1), 2 ** 30 - 1);
+  assert_equals(exports.makeI31(2 ** 30), -(2 ** 30));
+  assert_equals(exports.makeI31(-(2 ** 30)), -(2 ** 30));
+  assert_equals(exports.makeI31(2 ** 31 - 1), -1);
+  assert_equals(exports.makeI31(2 ** 31), 0);
+}, "i31ref conversion to Number");
+
+test(() => {
+  assert_equals(exports.getI31(exports.makeI31(42)), 42);
+  assert_equals(exports.getI31(42), 42);
+  assert_equals(exports.getI31(2.0 ** 30 - 1), 2 ** 30 - 1);
+  assert_equals(exports.getI31(-(2 ** 30)), -(2 ** 30));
+}, "Number conversion to i31ref");
+
+test(() => {
+  exports.argI31(null);
+  assert_throws_js(TypeError, () => exports.argI31(2 ** 30));
+  assert_throws_js(TypeError, () => exports.argI31(-(2 ** 30) - 1));
+  assert_throws_js(TypeError, () => exports.argI31(2n));
+  assert_throws_js(TypeError, () => exports.argI31(() => 3));
+  assert_throws_js(TypeError, () => exports.argI31(exports.getI31));
+}, "Check i31ref argument type");
+
+test(() => {
+  assert_equals(exports.castI31(42), 42);
+  assert_equals(exports.castI31(2 ** 30 - 1), 2 ** 30 - 1);
+  assert_throws_js(WebAssembly.RuntimeError, () => { exports.castI31(2 ** 30); });
+  assert_throws_js(WebAssembly.RuntimeError, () => { exports.castI31(-(2 ** 30) - 1); });
+  assert_throws_js(WebAssembly.RuntimeError, () => { exports.castI31(2 ** 32); });
+}, "Numbers in i31 range are i31ref, not hostref");
+
+test(() => {
+  assert_equals(exports.i31Global.value, 0);
+  exports.i31Global.value = 42;
+  assert_throws_js(TypeError, () => exports.i31Global.value = 2 ** 30);
+  assert_throws_js(TypeError, () => exports.i31Global.value = -(2 ** 30) - 1);
+  assert_equals(exports.i31Global.value, 42);
+}, "i31ref global");
+
+test(() => {
+  assert_equals(exports.i31Table.get(0), null);
+  exports.i31Table.set(0, 42);
+  assert_throws_js(TypeError, () => exports.i31Table.set(0, 2 ** 30));
+  assert_throws_js(TypeError, () => exports.i31Table.set(0, -(2 ** 30) - 1));
+  assert_equals(exports.i31Table.get(0), 42);
+}, "i31ref table");
diff --git a/test/fixtures/wpt/wasm/jsapi/global/constructor.any.js b/test/fixtures/wpt/wasm/jsapi/global/constructor.any.js
index dade7b1f55a4330..f83f77a5c3ecf34 100644
--- a/test/fixtures/wpt/wasm/jsapi/global/constructor.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/global/constructor.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function assert_Global(actual, expected) {
diff --git a/test/fixtures/wpt/wasm/jsapi/global/toString.any.js b/test/fixtures/wpt/wasm/jsapi/global/toString.any.js
index 359c4273b5bd786..b308498982ee5d6 100644
--- a/test/fixtures/wpt/wasm/jsapi/global/toString.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/global/toString.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 
 test(() => {
   const argument = { "value": "i32" };
diff --git a/test/fixtures/wpt/wasm/jsapi/global/type.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/global/type.tentative.any.js
index 95adc2af0f6813c..78d612529dd3f39 100644
--- a/test/fixtures/wpt/wasm/jsapi/global/type.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/global/type.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function assert_type(argument) {
diff --git a/test/fixtures/wpt/wasm/jsapi/global/value-get-set.any.js b/test/fixtures/wpt/wasm/jsapi/global/value-get-set.any.js
index f95b7ca9e3f0d54..bee5581f41814e2 100644
--- a/test/fixtures/wpt/wasm/jsapi/global/value-get-set.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/global/value-get-set.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 
 test(() => {
   const thisValues = [
diff --git a/test/fixtures/wpt/wasm/jsapi/global/valueOf.any.js b/test/fixtures/wpt/wasm/jsapi/global/valueOf.any.js
index 0695a5a61fbc6e2..5bcb17182589880 100644
--- a/test/fixtures/wpt/wasm/jsapi/global/valueOf.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/global/valueOf.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 
 test(() => {
   const argument = { "value": "i32" };
diff --git a/test/fixtures/wpt/wasm/jsapi/instance/constructor-bad-imports.any.js b/test/fixtures/wpt/wasm/jsapi/instance/constructor-bad-imports.any.js
index e4a5abb8eb2169f..1ef4f8423de857d 100644
--- a/test/fixtures/wpt/wasm/jsapi/instance/constructor-bad-imports.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/instance/constructor-bad-imports.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=/wasm/jsapi/bad-imports.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/instance/constructor-caching.any.js b/test/fixtures/wpt/wasm/jsapi/instance/constructor-caching.any.js
index 1aa4739b6294d01..f969364d93f4620 100644
--- a/test/fixtures/wpt/wasm/jsapi/instance/constructor-caching.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/instance/constructor-caching.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 function getExports() {
diff --git a/test/fixtures/wpt/wasm/jsapi/instance/constructor.any.js b/test/fixtures/wpt/wasm/jsapi/instance/constructor.any.js
index 26390ebd2cdb2e4..24bf97356c83a73 100644
--- a/test/fixtures/wpt/wasm/jsapi/instance/constructor.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/instance/constructor.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/instanceTestFactory.js
diff --git a/test/fixtures/wpt/wasm/jsapi/instance/exports.any.js b/test/fixtures/wpt/wasm/jsapi/instance/exports.any.js
index 6dcfbcee950d871..f7244923d83c510 100644
--- a/test/fixtures/wpt/wasm/jsapi/instance/exports.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/instance/exports.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 let emptyModuleBinary;
diff --git a/test/fixtures/wpt/wasm/jsapi/instance/toString.any.js b/test/fixtures/wpt/wasm/jsapi/instance/toString.any.js
index 547a9ca8295f5b6..d77037d65b9c25a 100644
--- a/test/fixtures/wpt/wasm/jsapi/instance/toString.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/instance/toString.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 test(() => {
diff --git a/test/fixtures/wpt/wasm/jsapi/instanceTestFactory.js b/test/fixtures/wpt/wasm/jsapi/instanceTestFactory.js
index ac468947ec22e29..2e015af8198a611 100644
--- a/test/fixtures/wpt/wasm/jsapi/instanceTestFactory.js
+++ b/test/fixtures/wpt/wasm/jsapi/instanceTestFactory.js
@@ -237,7 +237,7 @@ const instanceTestFactory = [
 
       builder.addGlobal(kWasmI32, true)
         .exportAs("")
-        .init = 7;
+        .init = wasmI32Const(7);
 
       const buffer = builder.toBuffer();
 
@@ -273,10 +273,10 @@ const instanceTestFactory = [
 
       builder.addGlobal(kWasmI32, true)
         .exportAs("global")
-        .init = 7;
+        .init = wasmI32Const(7);
       builder.addGlobal(kWasmF64, true)
         .exportAs("global2")
-        .init = 1.2;
+        .init = wasmF64Const(1.2);
 
       builder.addMemory(4, 8, true);
 
@@ -759,3 +759,5 @@ const instanceTestFactory = [
     }
   ],
 ];
+
+globalThis.instanceTestFactory = instanceTestFactory;
diff --git a/test/fixtures/wpt/wasm/jsapi/interface.any.js b/test/fixtures/wpt/wasm/jsapi/interface.any.js
index 19d29ead0a72644..8256fc209a7f650 100644
--- a/test/fixtures/wpt/wasm/jsapi/interface.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/interface.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function test_operations(object, object_name, operations) {
diff --git a/test/fixtures/wpt/wasm/jsapi/memory/constructor-shared.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/memory/constructor-shared.tentative.any.js
index 216fc4ca55591f1..0134b307749ed70 100644
--- a/test/fixtures/wpt/wasm/jsapi/memory/constructor-shared.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/memory/constructor-shared.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/memory/assertions.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/memory/constructor-types.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/memory/constructor-types.tentative.any.js
index d5378dbe82b00b9..4653c6686a78e47 100644
--- a/test/fixtures/wpt/wasm/jsapi/memory/constructor-types.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/memory/constructor-types.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/memory/assertions.js
 
@@ -17,4 +17,4 @@ test(() => {
     const argument = { minimum: 4 };
     const memory = new WebAssembly.Memory(argument);
     assert_Memory(memory, { "size": 4 });
-  }, "Non-zero minimum");
\ No newline at end of file
+  }, "Non-zero minimum");
diff --git a/test/fixtures/wpt/wasm/jsapi/memory/constructor.any.js b/test/fixtures/wpt/wasm/jsapi/memory/constructor.any.js
index 0a0be11e3708770..8f413c9f48a86de 100644
--- a/test/fixtures/wpt/wasm/jsapi/memory/constructor.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/memory/constructor.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/memory/assertions.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/memory/grow.any.js b/test/fixtures/wpt/wasm/jsapi/memory/grow.any.js
index c511129491f4de4..2eafe5761eaa6d2 100644
--- a/test/fixtures/wpt/wasm/jsapi/memory/grow.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/memory/grow.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/memory/assertions.js
 
 test(() => {
diff --git a/test/fixtures/wpt/wasm/jsapi/memory/type.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/memory/type.tentative.any.js
index a96a3227adca7ff..3f6531f5967ed74 100644
--- a/test/fixtures/wpt/wasm/jsapi/memory/type.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/memory/type.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function assert_type(argument) {
@@ -34,4 +34,4 @@ test(() => {
 
 test(() => {
     assert_type({ "minimum": 0, "maximum": 10, "shared": true});
-}, "shared memory");
\ No newline at end of file
+}, "shared memory");
diff --git a/test/fixtures/wpt/wasm/jsapi/module/constructor.any.js b/test/fixtures/wpt/wasm/jsapi/module/constructor.any.js
index 9978f7e6ac8f2b1..95604aabe475a85 100644
--- a/test/fixtures/wpt/wasm/jsapi/module/constructor.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/module/constructor.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=/wasm/jsapi/assertions.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/module/customSections.any.js b/test/fixtures/wpt/wasm/jsapi/module/customSections.any.js
index 4029877e92c7b8b..96958316e061d72 100644
--- a/test/fixtures/wpt/wasm/jsapi/module/customSections.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/module/customSections.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 function assert_ArrayBuffer(buffer, expected) {
diff --git a/test/fixtures/wpt/wasm/jsapi/module/exports.any.js b/test/fixtures/wpt/wasm/jsapi/module/exports.any.js
index 40a3935a4a23ba9..0c32e984a2cad1f 100644
--- a/test/fixtures/wpt/wasm/jsapi/module/exports.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/module/exports.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 let emptyModuleBinary;
@@ -109,10 +109,10 @@ test(() => {
 
   builder.addGlobal(kWasmI32, true)
     .exportAs("global")
-    .init = 7;
+    .init = wasmI32Const(7);
   builder.addGlobal(kWasmF64, true)
     .exportAs("global2")
-    .init = 1.2;
+    .init = wasmF64Const(1.2);
 
   builder.addMemory(0, 256, true);
 
@@ -167,7 +167,7 @@ test(() => {
 
   builder.addGlobal(kWasmI32, true)
     .exportAs("")
-    .init = 7;
+    .init = wasmI32Const(7);
 
   const buffer = builder.toBuffer()
   const module = new WebAssembly.Module(buffer);
diff --git a/test/fixtures/wpt/wasm/jsapi/module/imports.any.js b/test/fixtures/wpt/wasm/jsapi/module/imports.any.js
index ec550ce6c41af1d..2ab1725359f187c 100644
--- a/test/fixtures/wpt/wasm/jsapi/module/imports.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/module/imports.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 function assert_ModuleImportDescriptor(import_, expected) {
diff --git a/test/fixtures/wpt/wasm/jsapi/module/moduleSource.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/module/moduleSource.tentative.any.js
new file mode 100644
index 000000000000000..8a94cdd48cd497a
--- /dev/null
+++ b/test/fixtures/wpt/wasm/jsapi/module/moduleSource.tentative.any.js
@@ -0,0 +1,35 @@
+// META: global=window,dedicatedworker,jsshell,shadowrealm
+// META: script=/wasm/jsapi/wasm-module-builder.js
+// META: script=/wasm/jsapi/assertions.js
+
+let emptyModuleBinary;
+setup(() => {
+  emptyModuleBinary = new WasmModuleBuilder().toBuffer();
+});
+
+test(() => {
+  assert_equals(typeof AbstractModuleSource, "undefined");
+}, "AbstractModuleSource is not a global");
+
+test(() => {
+  const AbstractModuleSource = Object.getPrototypeOf(WebAssembly.Module);
+  assert_equals(AbstractModuleSource.name, "AbstractModuleSource");
+  assert_not_equals(AbstractModuleSource, Function);
+}, "AbstractModuleSource intrinsic");
+
+test(() => {
+  const AbstractModuleSourceProto = Object.getPrototypeOf(WebAssembly.Module.prototype);
+  assert_not_equals(AbstractModuleSourceProto, Object.prototype);
+  const AbstractModuleSource = Object.getPrototypeOf(WebAssembly.Module);
+  assert_equals(AbstractModuleSource.prototype, AbstractModuleSourceProto);
+}, "AbstractModuleSourceProto intrinsic");
+
+test(() => {
+  const module = new WebAssembly.Module(emptyModuleBinary);
+
+  const AbstractModuleSource = Object.getPrototypeOf(WebAssembly.Module);
+  const toStringTag = Object.getOwnPropertyDescriptor(AbstractModuleSource.prototype, Symbol.toStringTag).get;
+
+  assert_equals(toStringTag.call(module), "WebAssembly.Module");
+  assert_throws_js(TypeError, () => toStringTag.call({}));
+}, "AbstractModuleSourceProto toStringTag brand check");
\ No newline at end of file
diff --git a/test/fixtures/wpt/wasm/jsapi/module/toString.any.js b/test/fixtures/wpt/wasm/jsapi/module/toString.any.js
index 1c20cd6108c84e5..10c707979d5bdc1 100644
--- a/test/fixtures/wpt/wasm/jsapi/module/toString.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/module/toString.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
 test(() => {
diff --git a/test/fixtures/wpt/wasm/jsapi/prototypes.any.js b/test/fixtures/wpt/wasm/jsapi/prototypes.any.js
index 714f4f8430e5eb3..2316f7d9b4eeb5e 100644
--- a/test/fixtures/wpt/wasm/jsapi/prototypes.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/prototypes.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/wasm-module-builder.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/table/constructor-types.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/table/constructor-types.tentative.any.js
index 99ca41b55a9152b..b4015bdc6f7503d 100644
--- a/test/fixtures/wpt/wasm/jsapi/table/constructor-types.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/table/constructor-types.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/table/assertions.js
 
@@ -17,4 +17,4 @@ test(() => {
   const argument = { "element": "anyfunc", "minimum": 5 };
   const table = new WebAssembly.Table(argument);
   assert_Table(table, { "length": 5 });
-}, "Non-zero minimum");
\ No newline at end of file
+}, "Non-zero minimum");
diff --git a/test/fixtures/wpt/wasm/jsapi/table/constructor.any.js b/test/fixtures/wpt/wasm/jsapi/table/constructor.any.js
index 6d38d04e4f50503..51b1070d413586d 100644
--- a/test/fixtures/wpt/wasm/jsapi/table/constructor.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/table/constructor.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=/wasm/jsapi/assertions.js
 // META: script=/wasm/jsapi/table/assertions.js
diff --git a/test/fixtures/wpt/wasm/jsapi/table/get-set.any.js b/test/fixtures/wpt/wasm/jsapi/table/get-set.any.js
index 9301057a533ed48..abe6fecac9860c0 100644
--- a/test/fixtures/wpt/wasm/jsapi/table/get-set.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/table/get-set.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=assertions.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/table/grow.any.js b/test/fixtures/wpt/wasm/jsapi/table/grow.any.js
index 520d24bf4bafbb1..4038f1e64934b07 100644
--- a/test/fixtures/wpt/wasm/jsapi/table/grow.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/table/grow.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/wasm-module-builder.js
 // META: script=assertions.js
 
diff --git a/test/fixtures/wpt/wasm/jsapi/table/length.any.js b/test/fixtures/wpt/wasm/jsapi/table/length.any.js
index a9ef095ded44581..0e6de3f83e1ecf5 100644
--- a/test/fixtures/wpt/wasm/jsapi/table/length.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/table/length.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 
 test(() => {
   const thisValues = [
diff --git a/test/fixtures/wpt/wasm/jsapi/table/toString.any.js b/test/fixtures/wpt/wasm/jsapi/table/toString.any.js
index 8a09f2832c1d645..b5fb25b9c1e9545 100644
--- a/test/fixtures/wpt/wasm/jsapi/table/toString.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/table/toString.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 
 test(() => {
   const argument = { "element": "anyfunc", "initial": 0 };
diff --git a/test/fixtures/wpt/wasm/jsapi/table/type.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/table/type.tentative.any.js
index ef1ceecb17d695c..ef9bbc5aa4a228e 100644
--- a/test/fixtures/wpt/wasm/jsapi/table/type.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/table/type.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function assert_type(argument) {
diff --git a/test/fixtures/wpt/wasm/jsapi/tag/constructor.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/tag/constructor.tentative.any.js
index de63e7bf46d1e86..54edf8c8f59258f 100644
--- a/test/fixtures/wpt/wasm/jsapi/tag/constructor.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/tag/constructor.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 test(() => {
diff --git a/test/fixtures/wpt/wasm/jsapi/tag/toString.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/tag/toString.tentative.any.js
index ad9a4ba152f4f82..76fff0feef063d1 100644
--- a/test/fixtures/wpt/wasm/jsapi/tag/toString.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/tag/toString.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 
 test(() => {
   const argument = { parameters: [] };
diff --git a/test/fixtures/wpt/wasm/jsapi/tag/type.tentative.any.js b/test/fixtures/wpt/wasm/jsapi/tag/type.tentative.any.js
index 9d2f0de1a00f202..58c96078bfe39da 100644
--- a/test/fixtures/wpt/wasm/jsapi/tag/type.tentative.any.js
+++ b/test/fixtures/wpt/wasm/jsapi/tag/type.tentative.any.js
@@ -1,4 +1,4 @@
-// META: global=window,dedicatedworker,jsshell
+// META: global=window,dedicatedworker,jsshell,shadowrealm
 // META: script=/wasm/jsapi/assertions.js
 
 function assert_type(argument) {
diff --git a/test/fixtures/wpt/wasm/jsapi/wasm-module-builder.js b/test/fixtures/wpt/wasm/jsapi/wasm-module-builder.js
index 86d836a5a372451..1d8db0a6e6fd710 100644
--- a/test/fixtures/wpt/wasm/jsapi/wasm-module-builder.js
+++ b/test/fixtures/wpt/wasm/jsapi/wasm-module-builder.js
@@ -74,6 +74,13 @@ let kLocalNamesCode = 2;
 
 let kWasmFunctionTypeForm = 0x60;
 let kWasmAnyFunctionTypeForm = 0x70;
+let kWasmStructTypeForm = 0x5f;
+let kWasmArrayTypeForm = 0x5e;
+let kWasmSubtypeForm = 0x50;
+let kWasmSubtypeFinalForm = 0x4f;
+let kWasmRecursiveTypeGroupForm = 0x4e;
+
+let kNoSuperType = 0xFFFFFFFF;
 
 let kHasMaximumFlag = 1;
 let kSharedHasMaximumFlag = 3;
@@ -97,8 +104,43 @@ let kWasmI64 = 0x7e;
 let kWasmF32 = 0x7d;
 let kWasmF64 = 0x7c;
 let kWasmS128 = 0x7b;
-let kWasmAnyRef = 0x6f;
-let kWasmAnyFunc = 0x70;
+
+// These are defined as negative integers to distinguish them from positive type
+// indices.
+let kWasmNullFuncRef = -0x0d;
+let kWasmNullExternRef = -0x0e;
+let kWasmNullRef = -0x0f;
+let kWasmFuncRef = -0x10;
+let kWasmAnyFunc = kWasmFuncRef;  // Alias named as in the JS API spec
+let kWasmExternRef = -0x11;
+let kWasmAnyRef = -0x12;
+let kWasmEqRef = -0x13;
+let kWasmI31Ref = -0x14;
+let kWasmStructRef = -0x15;
+let kWasmArrayRef = -0x16;
+
+// Use the positive-byte versions inside function bodies.
+let kLeb128Mask = 0x7f;
+let kFuncRefCode = kWasmFuncRef & kLeb128Mask;
+let kAnyFuncCode = kFuncRefCode;  // Alias named as in the JS API spec
+let kExternRefCode = kWasmExternRef & kLeb128Mask;
+let kAnyRefCode = kWasmAnyRef & kLeb128Mask;
+let kEqRefCode = kWasmEqRef & kLeb128Mask;
+let kI31RefCode = kWasmI31Ref & kLeb128Mask;
+let kNullExternRefCode = kWasmNullExternRef & kLeb128Mask;
+let kNullFuncRefCode = kWasmNullFuncRef & kLeb128Mask;
+let kStructRefCode = kWasmStructRef & kLeb128Mask;
+let kArrayRefCode = kWasmArrayRef & kLeb128Mask;
+let kNullRefCode = kWasmNullRef & kLeb128Mask;
+
+let kWasmRefNull = 0x63;
+let kWasmRef = 0x64;
+function wasmRefNullType(heap_type) {
+  return {opcode: kWasmRefNull, heap_type: heap_type};
+}
+function wasmRefType(heap_type) {
+  return {opcode: kWasmRef, heap_type: heap_type};
+}
 
 let kExternalFunction = 0;
 let kExternalTable = 1;
@@ -146,14 +188,14 @@ let kSig_v_f = makeSig([kWasmF32], []);
 let kSig_f_f = makeSig([kWasmF32], [kWasmF32]);
 let kSig_f_d = makeSig([kWasmF64], [kWasmF32]);
 let kSig_d_d = makeSig([kWasmF64], [kWasmF64]);
-let kSig_r_r = makeSig([kWasmAnyRef], [kWasmAnyRef]);
+let kSig_r_r = makeSig([kWasmExternRef], [kWasmExternRef]);
 let kSig_a_a = makeSig([kWasmAnyFunc], [kWasmAnyFunc]);
-let kSig_i_r = makeSig([kWasmAnyRef], [kWasmI32]);
-let kSig_v_r = makeSig([kWasmAnyRef], []);
+let kSig_i_r = makeSig([kWasmExternRef], [kWasmI32]);
+let kSig_v_r = makeSig([kWasmExternRef], []);
 let kSig_v_a = makeSig([kWasmAnyFunc], []);
-let kSig_v_rr = makeSig([kWasmAnyRef, kWasmAnyRef], []);
+let kSig_v_rr = makeSig([kWasmExternRef, kWasmExternRef], []);
 let kSig_v_aa = makeSig([kWasmAnyFunc, kWasmAnyFunc], []);
-let kSig_r_v = makeSig([], [kWasmAnyRef]);
+let kSig_r_v = makeSig([], [kWasmExternRef]);
 let kSig_a_v = makeSig([], [kWasmAnyFunc]);
 let kSig_a_i = makeSig([kWasmI32], [kWasmAnyFunc]);
 
@@ -374,10 +416,50 @@ let kExprRefIsNull = 0xd1;
 let kExprRefFunc = 0xd2;
 
 // Prefix opcodes
+let kGCPrefix = 0xfb;
 let kNumericPrefix = 0xfc;
 let kSimdPrefix = 0xfd;
 let kAtomicPrefix = 0xfe;
 
+// Use these for multi-byte instructions (opcode > 0x7F needing two LEB bytes):
+function GCInstr(opcode) {
+  if (opcode <= 0x7F) return [kGCPrefix, opcode];
+  return [kGCPrefix, 0x80 | (opcode & 0x7F), opcode >> 7];
+}
+
+// GC opcodes
+let kExprStructNew = 0x00;
+let kExprStructNewDefault = 0x01;
+let kExprStructGet = 0x02;
+let kExprStructGetS = 0x03;
+let kExprStructGetU = 0x04;
+let kExprStructSet = 0x05;
+let kExprArrayNew = 0x06;
+let kExprArrayNewDefault = 0x07;
+let kExprArrayNewFixed = 0x08;
+let kExprArrayNewData = 0x09;
+let kExprArrayNewElem = 0x0a;
+let kExprArrayGet = 0x0b;
+let kExprArrayGetS = 0x0c;
+let kExprArrayGetU = 0x0d;
+let kExprArraySet = 0x0e;
+let kExprArrayLen = 0x0f;
+let kExprArrayFill = 0x10;
+let kExprArrayCopy = 0x11;
+let kExprArrayInitData = 0x12;
+let kExprArrayInitElem = 0x13;
+let kExprRefTest = 0x14;
+let kExprRefTestNull = 0x15;
+let kExprRefCast = 0x16;
+let kExprRefCastNull = 0x17;
+let kExprBrOnCast = 0x18;
+let kExprBrOnCastFail = 0x19;
+let kExprExternInternalize = 0x1a;
+let kExprExternExternalize = 0x1b;
+let kExprI31New = 0x1c;
+let kExprI31GetS = 0x1d;
+let kExprI31GetU = 0x1e;
+
 // Numeric opcodes.
 let kExprMemoryInit = 0x08;
 let kExprDataDrop = 0x09;
@@ -554,6 +636,25 @@ class Binary {
     }
   }
 
+  emit_heap_type(heap_type) {
+    this.emit_bytes(wasmSignedLeb(heap_type, kMaxVarInt32Size));
+  }
+
+  emit_type(type) {
+    if ((typeof type) == 'number') {
+      this.emit_u8(type >= 0 ? type : type & kLeb128Mask);
+    } else {
+      this.emit_u8(type.opcode);
+      if ('depth' in type) this.emit_u8(type.depth);
+      this.emit_heap_type(type.heap_type);
+    }
+  }
+
+  emit_init_expr(expr) {
+    this.emit_bytes(expr);
+    this.emit_u8(kExprEnd);
+  }
+
   emit_header() {
     this.emit_bytes([
       kWasmH0, kWasmH1, kWasmH2, kWasmH3, kWasmV0, kWasmV1, kWasmV2, kWasmV3
@@ -644,11 +745,11 @@ class WasmFunctionBuilder {
 }
 
 class WasmGlobalBuilder {
-  constructor(module, type, mutable) {
+  constructor(module, type, mutable, init) {
     this.module = module;
     this.type = type;
     this.mutable = mutable;
-    this.init = 0;
+    this.init = init;
   }
 
   exportAs(name) {
@@ -658,13 +759,24 @@ class WasmGlobalBuilder {
   }
 }
 
+function checkExpr(expr) {
+  for (let b of expr) {
+    if (typeof b !== 'number' || (b & (~0xFF)) !== 0) {
+      throw new Error(
+          'invalid body (entries must be 8 bit numbers): ' + expr);
+    }
+  }
+}
+
 class WasmTableBuilder {
-  constructor(module, type, initial_size, max_size) {
+  constructor(module, type, initial_size, max_size, init_expr) {
     this.module = module;
     this.type = type;
     this.initial_size = initial_size;
     this.has_max = max_size != undefined;
     this.max_size = max_size;
+    this.init_expr = init_expr;
+    this.has_init = init_expr !== undefined;
   }
 
   exportAs(name) {
@@ -674,6 +786,35 @@ class WasmTableBuilder {
   }
 }
 
+function makeField(type, mutability) {
+  if ((typeof mutability) != 'boolean') {
+    throw new Error('field mutability must be boolean');
+  }
+  return {type: type, mutability: mutability};
+}
+
+class WasmStruct {
+  constructor(fields, is_final, supertype_idx) {
+    if (!Array.isArray(fields)) {
+      throw new Error('struct fields must be an array');
+    }
+    this.fields = fields;
+    this.type_form = kWasmStructTypeForm;
+    this.is_final = is_final;
+    this.supertype = supertype_idx;
+  }
+}
+
+class WasmArray {
+  constructor(type, mutability, is_final, supertype_idx) {
+    this.type = type;
+    this.mutability = mutability;
+    this.type_form = kWasmArrayTypeForm;
+    this.is_final = is_final;
+    this.supertype = supertype_idx;
+  }
+}
+
 class WasmModuleBuilder {
   constructor() {
     this.types = [];
@@ -686,6 +827,7 @@ class WasmModuleBuilder {
     this.element_segments = [];
     this.data_segments = [];
     this.explicit = [];
+    this.rec_groups = [];
     this.num_imported_funcs = 0;
     this.num_imported_globals = 0;
     this.num_imported_tables = 0;
@@ -728,25 +870,65 @@ class WasmModuleBuilder {
     this.explicit.push(this.createCustomSection(name, bytes));
   }
 
-  addType(type) {
-    this.types.push(type);
-    var pl = type.params.length;  // should have params
-    var rl = type.results.length; // should have results
+  // We use {is_final = true} so that the MVP syntax is generated for
+  // signatures.
+  addType(type, supertype_idx = kNoSuperType, is_final = true) {
+    var pl = type.params.length;   // should have params
+    var rl = type.results.length;  // should have results
+    var type_copy = {params: type.params, results: type.results,
+                     is_final: is_final, supertype: supertype_idx};
+    this.types.push(type_copy);
+    return this.types.length - 1;
+  }
+
+  addStruct(fields, supertype_idx = kNoSuperType, is_final = false) {
+    this.types.push(new WasmStruct(fields, is_final, supertype_idx));
     return this.types.length - 1;
   }
 
-  addGlobal(local_type, mutable) {
-    let glob = new WasmGlobalBuilder(this, local_type, mutable);
+  addArray(type, mutability, supertype_idx = kNoSuperType, is_final = false) {
+    this.types.push(new WasmArray(type, mutability, is_final, supertype_idx));
+    return this.types.length - 1;
+  }
+
+  static defaultFor(type) {
+    switch (type) {
+      case kWasmI32:
+        return wasmI32Const(0);
+      case kWasmI64:
+        return wasmI64Const(0);
+      case kWasmF32:
+        return wasmF32Const(0.0);
+      case kWasmF64:
+        return wasmF64Const(0.0);
+      case kWasmS128:
+        return [kSimdPrefix, kExprS128Const, ...(new Array(16).fill(0))];
+      default:
+        if ((typeof type) != 'number' && type.opcode != kWasmRefNull) {
+          throw new Error("Non-defaultable type");
+        }
+        let heap_type = (typeof type) == 'number' ? type : type.heap_type;
+        return [kExprRefNull, ...wasmSignedLeb(heap_type, kMaxVarInt32Size)];
+    }
+  }
+
+  addGlobal(type, mutable, init) {
+    if (init === undefined) init = WasmModuleBuilder.defaultFor(type);
+    checkExpr(init);
+    let glob = new WasmGlobalBuilder(this, type, mutable, init);
     glob.index = this.globals.length + this.num_imported_globals;
     this.globals.push(glob);
     return glob;
   }
 
-  addTable(type, initial_size, max_size = undefined) {
-    if (type != kWasmAnyRef && type != kWasmAnyFunc) {
-      throw new Error('Tables must be of type kWasmAnyRef or kWasmAnyFunc');
+  addTable(type, initial_size, max_size = undefined, init_expr = undefined) {
+    if (type == kWasmI32 || type == kWasmI64 || type == kWasmF32 ||
+        type == kWasmF64 || type == kWasmS128 || type == kWasmStmt) {
+      throw new Error('Tables must be of a reference type');
     }
-    let table = new WasmTableBuilder(this, type, initial_size, max_size);
+    if (init_expr != undefined) checkExpr(init_expr);
+    let table = new WasmTableBuilder(
+        this, type, initial_size, max_size, init_expr);
     table.index = this.tables.length + this.num_imported_tables;
     this.tables.push(table);
     return table;
@@ -754,9 +936,9 @@ class WasmModuleBuilder {
 
   addTag(type) {
     let type_index = (typeof type) == "number" ? type : this.addType(type);
-    let except_index = this.tags.length + this.num_imported_tags;
+    let tag_index = this.tags.length + this.num_imported_tags;
     this.tags.push(type_index);
-    return except_index;
+    return tag_index;
   }
 
   addFunction(name, type) {
@@ -877,6 +1059,21 @@ class WasmModuleBuilder {
     return this;
   }
 
+  startRecGroup() {
+    this.rec_groups.push({start: this.types.length, size: 0});
+  }
+
+  endRecGroup() {
+    if (this.rec_groups.length == 0) {
+      throw new Error("Did not start a recursive group before ending one")
+    }
+    let last_element = this.rec_groups[this.rec_groups.length - 1]
+    if (last_element.size != 0) {
+      throw new Error("Did not start a recursive group before ending one")
+    }
+    last_element.size = this.types.length - last_element.start;
+  }
+
   setName(name) {
     this.name = name;
     return this;
@@ -891,18 +1088,55 @@ class WasmModuleBuilder {
 
     // Add type section
     if (wasm.types.length > 0) {
-      if (debug) print("emitting types @ " + binary.length);
+      if (debug) print('emitting types @ ' + binary.length);
       binary.emit_section(kTypeSectionCode, section => {
-        section.emit_u32v(wasm.types.length);
-        for (let type of wasm.types) {
-          section.emit_u8(kWasmFunctionTypeForm);
-          section.emit_u32v(type.params.length);
-          for (let param of type.params) {
-            section.emit_u8(param);
+        let length_with_groups = wasm.types.length;
+        for (let group of wasm.rec_groups) {
+          length_with_groups -= group.size - 1;
+        }
+        section.emit_u32v(length_with_groups);
+
+        let rec_group_index = 0;
+
+        for (let i = 0; i < wasm.types.length; i++) {
+          if (rec_group_index < wasm.rec_groups.length &&
+              wasm.rec_groups[rec_group_index].start == i) {
+            section.emit_u8(kWasmRecursiveTypeGroupForm);
+            section.emit_u32v(wasm.rec_groups[rec_group_index].size);
+            rec_group_index++;
           }
-          section.emit_u32v(type.results.length);
-          for (let result of type.results) {
-            section.emit_u8(result);
+
+          let type = wasm.types[i];
+          if (type.supertype != kNoSuperType) {
+            section.emit_u8(type.is_final ? kWasmSubtypeFinalForm
+                                          : kWasmSubtypeForm);
+            section.emit_u8(1);  // supertype count
+            section.emit_u32v(type.supertype);
+          } else if (!type.is_final) {
+            section.emit_u8(kWasmSubtypeForm);
+            section.emit_u8(0);  // no supertypes
+          }
+          if (type instanceof WasmStruct) {
+            section.emit_u8(kWasmStructTypeForm);
+            section.emit_u32v(type.fields.length);
+            for (let field of type.fields) {
+              section.emit_type(field.type);
+              section.emit_u8(field.mutability ? 1 : 0);
+            }
+          } else if (type instanceof WasmArray) {
+            section.emit_u8(kWasmArrayTypeForm);
+            section.emit_type(type.type);
+            section.emit_u8(type.mutability ? 1 : 0);
+          } else {
+            section.emit_u8(kWasmFunctionTypeForm);
+            section.emit_u32v(type.params.length);
+            for (let param of type.params) {
+              section.emit_type(param);
+            }
+            section.emit_u32v(type.results.length);
+            for (let result of type.results) {
+              section.emit_type(result);
+            }
           }
         }
       });
@@ -918,9 +1152,9 @@ class WasmModuleBuilder {
           section.emit_string(imp.name || '');
           section.emit_u8(imp.kind);
           if (imp.kind == kExternalFunction) {
-            section.emit_u32v(imp.type);
+            section.emit_u32v(imp.type_index);
           } else if (imp.kind == kExternalGlobal) {
-            section.emit_u32v(imp.type);
+            section.emit_type(imp.type);
             section.emit_u8(imp.mutable);
           } else if (imp.kind == kExternalMemory) {
             var has_max = (typeof imp.maximum) != "undefined";
@@ -933,7 +1167,7 @@ class WasmModuleBuilder {
             section.emit_u32v(imp.initial); // initial
             if (has_max) section.emit_u32v(imp.maximum); // maximum
           } else if (imp.kind == kExternalTable) {
-            section.emit_u8(imp.type);
+            section.emit_type(imp.type);
             var has_max = (typeof imp.maximum) != "undefined";
             section.emit_u8(has_max ? 1 : 0); // flags
             section.emit_u32v(imp.initial); // initial
@@ -965,10 +1199,11 @@ class WasmModuleBuilder {
       binary.emit_section(kTableSectionCode, section => {
         section.emit_u32v(wasm.tables.length);
         for (let table of wasm.tables) {
-          section.emit_u8(table.type);
+          section.emit_type(table.type);
           section.emit_u8(table.has_max);
           section.emit_u32v(table.initial_size);
           if (table.has_max) section.emit_u32v(table.max_size);
+          if (table.has_init) section.emit_init_expr(table.init_expr);
         }
       });
     }
@@ -997,41 +1232,9 @@ class WasmModuleBuilder {
       binary.emit_section(kGlobalSectionCode, section => {
         section.emit_u32v(wasm.globals.length);
         for (let global of wasm.globals) {
-          section.emit_u8(global.type);
+          section.emit_type(global.type);
           section.emit_u8(global.mutable);
-          if ((typeof global.init_index) == "undefined") {
-            // Emit a constant initializer.
-            switch (global.type) {
-            case kWasmI32:
-              section.emit_u8(kExprI32Const);
-              section.emit_u32v(global.init);
-              break;
-            case kWasmI64:
-              section.emit_u8(kExprI64Const);
-              section.emit_u64v(global.init);
-              break;
-            case kWasmF32:
-              section.emit_bytes(wasmF32Const(global.init));
-              break;
-            case kWasmF64:
-              section.emit_bytes(wasmF64Const(global.init));
-              break;
-            case kWasmAnyFunc:
-            case kWasmAnyRef:
-              if (global.function_index !== undefined) {
-                section.emit_u8(kExprRefFunc);
-                section.emit_u32v(global.function_index);
-              } else {
-                section.emit_u8(kExprRefNull);
-              }
-              break;
-            }
-          } else {
-            // Emit a global-index initializer.
-            section.emit_u8(kExprGlobalGet);
-            section.emit_u32v(global.init_index);
-          }
-          section.emit_u8(kExprEnd);  // end of init expression
+          section.emit_init_expr(global.init);
         }
       });
     }
@@ -1161,7 +1364,7 @@ class WasmModuleBuilder {
               local_decls.push({count: l.s128_count, type: kWasmS128});
             }
             if (l.anyref_count > 0) {
-              local_decls.push({count: l.anyref_count, type: kWasmAnyRef});
+              local_decls.push({count: l.anyref_count, type: kWasmExternRef});
             }
             if (l.anyfunc_count > 0) {
               local_decls.push({count: l.anyfunc_count, type: kWasmAnyFunc});
@@ -1171,7 +1374,7 @@ class WasmModuleBuilder {
           header.emit_u32v(local_decls.length);
           for (let decl of local_decls) {
             header.emit_u32v(decl.count);
-            header.emit_u8(decl.type);
+            header.emit_type(decl.type);
           }
 
           section.emit_u32v(header.length + func.body.length);
@@ -1284,6 +1487,7 @@ class WasmModuleBuilder {
     return new WebAssembly.Module(this.toBuffer(debug));
   }
 }
+globalThis.WasmModuleBuilder = WasmModuleBuilder;
 
 function wasmSignedLeb(val, max_len = 5) {
   let res = [];
@@ -1300,10 +1504,12 @@ function wasmSignedLeb(val, max_len = 5) {
   throw new Error(
       'Leb value <' + val + '> exceeds maximum length of ' + max_len);
 }
+globalThis.wasmSignedLeb = wasmSignedLeb;
 
 function wasmI32Const(val) {
   return [kExprI32Const, ...wasmSignedLeb(val, 5)];
 }
+globalThis.wasmI32Const = wasmI32Const;
 
 function wasmF32Const(f) {
   // Write in little-endian order at offset 0.
@@ -1312,6 +1518,7 @@ function wasmF32Const(f) {
     kExprF32Const, byte_view[0], byte_view[1], byte_view[2], byte_view[3]
   ];
 }
+globalThis.wasmI32Const = wasmI32Const;
 
 function wasmF64Const(f) {
   // Write in little-endian order at offset 0.
@@ -1321,3 +1528,4 @@ function wasmF64Const(f) {
     byte_view[3], byte_view[4], byte_view[5], byte_view[6], byte_view[7]
   ];
 }
+globalThis.wasmF64Const = wasmF64Const;
diff --git a/test/fixtures/wpt/wasm/webapi/esm-integration/resources/worker-source-phase.js b/test/fixtures/wpt/wasm/webapi/esm-integration/resources/worker-source-phase.js
new file mode 100644
index 000000000000000..e1c2703899a50d1
--- /dev/null
+++ b/test/fixtures/wpt/wasm/webapi/esm-integration/resources/worker-source-phase.js
@@ -0,0 +1,10 @@
+import source modSource from "./worker.wasm";
+import { pm } from "./worker-helper.js";
+assert_true(modSource instanceof WebAssembly.Module);
+assert_true(await import.source("./worker.wasm") === modSource);
+
+await WebAssembly.instantiate(modSource, {
+  "./worker-helper.js": {
+    "pm": pm
+  }
+});
\ No newline at end of file
diff --git a/test/fixtures/wpt/wasm/webapi/esm-integration/resources/worker.js b/test/fixtures/wpt/wasm/webapi/esm-integration/resources/worker.js
index c72464f71a45614..1163e477fd7270d 100644
--- a/test/fixtures/wpt/wasm/webapi/esm-integration/resources/worker.js
+++ b/test/fixtures/wpt/wasm/webapi/esm-integration/resources/worker.js
@@ -1 +1,2 @@
-import * as mod from "./worker.wasm"
+import * as mod from "./worker.wasm";
+assert_true(await import("./worker.wasm") === mod);
diff --git a/test/fixtures/wpt/wasm/webapi/esm-integration/script-src-allows-wasm.tentative.html b/test/fixtures/wpt/wasm/webapi/esm-integration/script-src-allows-wasm.tentative.html
new file mode 100644
index 000000000000000..07faf9a5a1cff52
--- /dev/null
+++ b/test/fixtures/wpt/wasm/webapi/esm-integration/script-src-allows-wasm.tentative.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<title>script-src allows Wasm execution</title>
+<meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+    setup({allow_uncaught_exception: true});
+
+    const test_load = async_test(
+        "Importing a WebAssembly module should be allowed by script-src CSP.");
+
+    window.log = [];
+    document.addEventListener("securitypolicyviolation", (e) => {
+      window.log.push(e.violatedDirective);
+    });
+
+    window.addEventListener("load", test_load.step_func_done(ev => {
+      assert_array_equals(log, ["executed"]);
+    }));
+</script>
+<script type="module" src="./resources/execute-start.wasm"></script>
diff --git a/test/fixtures/wpt/wasm/webapi/esm-integration/script-src-blocks-wasm.tentative.sub.html b/test/fixtures/wpt/wasm/webapi/esm-integration/script-src-blocks-wasm.tentative.sub.html
new file mode 100644
index 000000000000000..0d5c7ca6ed57fd8
--- /dev/null
+++ b/test/fixtures/wpt/wasm/webapi/esm-integration/script-src-blocks-wasm.tentative.sub.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<title>script-src blocks Wasm execution</title>
+<meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+    setup({allow_uncaught_exception: true});
+
+    const test_load = async_test(
+        "Importing a WebAssembly module should be guarded by script-src CSP.");
+
+    window.log = [];
+    document.addEventListener("securitypolicyviolation", (e) => {
+      window.log.push(e.violatedDirective);
+    });
+
+    window.addEventListener("load", test_load.step_func_done(ev => {
+      assert_array_equals(log, ["script-src-elem"]);
+    }));
+</script>
+<script type="module" src="https://{{hosts[alt][]}}/resources/execute-start.wasm"></script>
diff --git a/test/fixtures/wpt/wasm/webapi/esm-integration/source-phase.tentative.html b/test/fixtures/wpt/wasm/webapi/esm-integration/source-phase.tentative.html
new file mode 100644
index 000000000000000..870b16bd0a0ce8d
--- /dev/null
+++ b/test/fixtures/wpt/wasm/webapi/esm-integration/source-phase.tentative.html
@@ -0,0 +1,35 @@
+<!doctype html>
+<title>Source phase imports</title>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script type=module>
+setup({ single_test: true });
+
+import source exportedNamesSource from "./resources/exported-names.wasm";
+
+assert_true(exportedNamesSource instanceof WebAssembly.Module);
+const AbstractModuleSource = Object.getPrototypeOf(WebAssembly.Module);
+assert_equals(AbstractModuleSource.name, "AbstractModuleSource");
+assert_true(exportedNamesSource instanceof AbstractModuleSource);
+
+assert_array_equals(WebAssembly.Module.exports(exportedNamesSource).map(({ name }) => name).sort(),
+                    ["func", "glob", "mem", "tab"]);
+
+const wasmImportFromWasmSource = await import.source("./resources/wasm-import-from-wasm.wasm");
+
+assert_true(wasmImportFromWasmSource instanceof WebAssembly.Module);
+
+let logged = false;
+const instance = await WebAssembly.instantiate(wasmImportFromWasmSource, {
+  "./wasm-export-to-wasm.wasm": {
+    log () {
+      logged = true;
+    }
+  }
+});
+instance.exports.logExec();
+assert_true(logged);
+
+done();
+</script>
diff --git a/test/fixtures/wpt/wasm/webapi/esm-integration/worker-import-source-phase.tentative.html b/test/fixtures/wpt/wasm/webapi/esm-integration/worker-import-source-phase.tentative.html
new file mode 100644
index 000000000000000..e193f3efc693307
--- /dev/null
+++ b/test/fixtures/wpt/wasm/webapi/esm-integration/worker-import-source-phase.tentative.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<title>Testing import of WebAssembly source phase from JavaScript worker</title>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script type=module>
+setup({ single_test: true });
+const worker = new Worker("resources/worker-source-phase.js", { type: "module" });
+worker.onmessage = (msg) => {
+  assert_equals(msg.data, 42);
+  done();
+}
+</script>
diff --git a/test/fixtures/wpt/wasm/webapi/esm-integration/worker.tentative.html b/test/fixtures/wpt/wasm/webapi/esm-integration/worker.tentative.html
index 8002e07ce7f1cfe..6145dd04ff8c8d3 100644
--- a/test/fixtures/wpt/wasm/webapi/esm-integration/worker.tentative.html
+++ b/test/fixtures/wpt/wasm/webapi/esm-integration/worker.tentative.html
@@ -10,4 +10,7 @@
   assert_equals(msg, 42);
   done();
 }
+worker.onerror = () => {
+  assert_unreached("worker got an error");
+}
 </script>
diff --git a/test/fixtures/wpt/webmessaging/broadcastchannel/WEB_FEATURES.yml b/test/fixtures/wpt/webmessaging/broadcastchannel/WEB_FEATURES.yml
new file mode 100644
index 000000000000000..378ed57dc52d077
--- /dev/null
+++ b/test/fixtures/wpt/webmessaging/broadcastchannel/WEB_FEATURES.yml
@@ -0,0 +1,3 @@
+features:
+- name: broadcast-channel
+  files: "**"
diff --git a/test/fixtures/wpt/webmessaging/broadcastchannel/basics.any.js b/test/fixtures/wpt/webmessaging/broadcastchannel/basics.any.js
index 68b4706028f5aaf..eec09d65a3aba27 100644
--- a/test/fixtures/wpt/webmessaging/broadcastchannel/basics.any.js
+++ b/test/fixtures/wpt/webmessaging/broadcastchannel/basics.any.js
@@ -1,3 +1,11 @@
+test(function() {
+  assert_throws_js(
+      TypeError,
+      () => BroadcastChannel(""),
+      "Calling BroadcastChannel constructor without 'new' must throw"
+    );
+}, "BroadcastChannel constructor called as normal function");
+
 async_test(t => {
     let c1 = new BroadcastChannel('eventType');
     let c2 = new BroadcastChannel('eventType');
diff --git a/test/fixtures/wpt/webstorage/localstorage-about-blank-3P-iframe-opens-3P-window.partitioned.tentative.html b/test/fixtures/wpt/webstorage/localstorage-about-blank-3P-iframe-opens-3P-window.partitioned.html
similarity index 100%
rename from test/fixtures/wpt/webstorage/localstorage-about-blank-3P-iframe-opens-3P-window.partitioned.tentative.html
rename to test/fixtures/wpt/webstorage/localstorage-about-blank-3P-iframe-opens-3P-window.partitioned.html
diff --git a/test/fixtures/wpt/webstorage/localstorage-basic-partitioned.tentative.sub.html b/test/fixtures/wpt/webstorage/localstorage-basic-partitioned.sub.html
similarity index 97%
rename from test/fixtures/wpt/webstorage/localstorage-basic-partitioned.tentative.sub.html
rename to test/fixtures/wpt/webstorage/localstorage-basic-partitioned.sub.html
index 7ed49b1e9a0eb5f..3d5b1e93ce5ef66 100644
--- a/test/fixtures/wpt/webstorage/localstorage-basic-partitioned.tentative.sub.html
+++ b/test/fixtures/wpt/webstorage/localstorage-basic-partitioned.sub.html
@@ -38,7 +38,7 @@
       assert_true(typeof sameSiteID === "string");
 
       if (location.origin !== altOrigin) {
-        crossSiteWindow = window.open(`${altOrigin}/webstorage/localstorage-basic-partitioned.tentative.sub.html`, "", "noopener=false");
+        crossSiteWindow = window.open(`${altOrigin}/webstorage/localstorage-basic-partitioned.sub.html`, "", "noopener=false");
         t.add_cleanup(() => crossSiteWindow.close());
       }
     }
diff --git a/test/fixtures/wpt/webstorage/localstorage-cross-origin-iframe.tentative.https.window.js b/test/fixtures/wpt/webstorage/localstorage-cross-origin-iframe.https.window.js
similarity index 100%
rename from test/fixtures/wpt/webstorage/localstorage-cross-origin-iframe.tentative.https.window.js
rename to test/fixtures/wpt/webstorage/localstorage-cross-origin-iframe.https.window.js
diff --git a/test/fixtures/wpt/webstorage/sessionStorage-basic-partitioned.tentative.sub.html b/test/fixtures/wpt/webstorage/sessionStorage-basic-partitioned.sub.html
similarity index 97%
rename from test/fixtures/wpt/webstorage/sessionStorage-basic-partitioned.tentative.sub.html
rename to test/fixtures/wpt/webstorage/sessionStorage-basic-partitioned.sub.html
index 30575bfaf1a579a..38525b99a23497a 100644
--- a/test/fixtures/wpt/webstorage/sessionStorage-basic-partitioned.tentative.sub.html
+++ b/test/fixtures/wpt/webstorage/sessionStorage-basic-partitioned.sub.html
@@ -47,7 +47,7 @@
       // new cross-site window that contains our shared-iframe to repeat
       // the process in a cross-site environment.
       if (location.origin !== altOrigin) {
-        crossSiteWindow = window.open(`${altOrigin}/webstorage/sessionStorage-basic-partitioned.tentative.sub.html`, "", "noopener=false");
+        crossSiteWindow = window.open(`${altOrigin}/webstorage/sessionStorage-basic-partitioned.sub.html`, "", "noopener=false");
         t.add_cleanup(() => crossSiteWindow.close());
       }
     }