Revisit if "document's body element" matches impl

[zcorpan]

https://quirks.spec.whatwg.org/commit-snapshots/cb6144cca6722f8c669539633af6d4015cb8fb08/#ref-for-documents-body-element①

See web-platform-tests/wpt#9628

[foolip]

@mstensho, would you happen to know where in Blink I can find the implementation of this quirk, to compare the conditions?

[mstensho]

Here?

https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/layout/LayoutBox.cpp?l=3354&rcl=2fefc4bd0b63b9be05846fddaaf47047f103544c

[foolip]

Ah, so that seems to also include https://quirks.spec.whatwg.org/commit-snapshots/cb6144cca6722f8c669539633af6d4015cb8fb08/#the-html-element-fills-the-viewport-quirk. @zcorpan, do you know if these two quirks are tied in other implementations too?

AFAICT, the "The computed value of the width property of body is auto" just doesn't appear in Blink, and I can't trivially tell if the rest matches, but it's surely similar. I can't tell exactly what difference would explain the differences in test results, and wonder if maybe it's really the "The html element fills the viewport quirk" quirk influencing this?