feat(hls): Add config to prefer native HLS playback

Closes shaka-project#3077

Change-Id: Ib49270c17656e50cd68806836d7b71ee8e0bc148

demo/common/message_ids.js

@@ -199,6 +199,7 @@ shakaDemo.MessageIds = {
   NUMBER_NONZERO_INTEGER_WARNING: 'DEMO_NUMBER_NONZERO_INTEGER_WARNING',
   OFFLINE_SECTION_HEADER: 'DEMO_OFFLINE_SECTION_HEADER',
   PREFER_FORCED_SUBS: 'DEMO_PREFER_FORCED_SUBS',
+  PREFER_NATIVE_HLS: 'DEMO_PREFER_NATIVE_HLS',
   REBUFFERING_GOAL: 'DEMO_REBUFFERING_GOAL',
   RESTRICTIONS_SECTION_HEADER: 'DEMO_RESTRICTIONS_SECTION_HEADER',
   SAFE_SEEK_OFFSET: 'DEMO_SAFE_SEEK_OFFSET',

demo/config.js

@@ -323,7 +323,9 @@ shakaDemo.Config = class {
         .addBoolInput_(MessageIds.AUTO_LOW_LATENCY,
             'streaming.autoLowLatencyMode')
         .addBoolInput_(MessageIds.FORCE_HTTPS,
-            'streaming.forceHTTPS');
+            'streaming.forceHTTPS')
+        .addBoolInput_(MessageIds.PREFER_NATIVE_HLS,
+            'streaming.preferNativeHls');
 
     if (!shakaDemoMain.getNativeControlsEnabled()) {
       this.addBoolInput_(MessageIds.ALWAYS_STREAM_TEXT,

demo/locales/en.json

@@ -144,6 +144,7 @@
   "DEMO_PLAY": "Play",
   "DEMO_PLAYREADY": "PlayReady DRM",
   "DEMO_PREFER_FORCED_SUBS": "Prefer Forced Subs",
+  "DEMO_PREFER_NATIVE_HLS": "Prefer native HLS playback when available",
   "DEMO_PROJECT_LINKS_HEADER": "PROJECT LINKS",
   "DEMO_PROMPT_NO": "No",
   "DEMO_PROMPT_YES": "Yes",

demo/locales/source.json

@@ -579,6 +579,10 @@
     "description": "The name of a configuration value.",
     "message": "Prefer Forced Subs"
   },
+  "DEMO_PREFER_NATIVE_HLS": {
+    "description": "The name of a configuration value.",
+    "message": "Prefer native HLS playback when available"
+  },
   "DEMO_PROJECT_LINKS_HEADER": {
     "description": "A header for a section of the footer, that contains links to various project-related things.",
     "message": "PROJECT LINKS"

externs/shaka/player.js

@@ -730,7 +730,8 @@ shaka.extern.ManifestConfiguration;
  *   inaccurateManifestTolerance: number,
  *   lowLatencyMode: boolean,
  *   autoLowLatencyMode: boolean,
- *   forceHTTPS: boolean
+ *   forceHTTPS: boolean,
+ *   preferNativeHls: boolean
  * }}
  *
  * @description
@@ -831,6 +832,8 @@ shaka.extern.ManifestConfiguration;
  *   activate the lowLatencyMode. Defaults to false.
  * @property {boolean} forceHTTPS
  *   If true, if the protocol is HTTP change it to HTTPs.
+ * @property {boolean} preferNativeHls
+ *   If true, prefer native HLS playback when possible, regardless of platform.
  *
  * @exportDoc
  */

lib/player.js

@@ -1175,9 +1175,21 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
 
       // We would prefer MediaSource in some cases, and src= in others.  For
       // example, Android has native HLS, but we'd prefer our own MediaSource
-      // version there.  For Safari, the choice is governed by the
-      // useNativeHlsOnSafari setting of the streaming config.
-      return Platform.isApple() && this.config_.streaming.useNativeHlsOnSafari;
+      // version there.
+
+      // Native HLS can be preferred on any platform via this flag:
+      if (this.config_.streaming.preferNativeHls) {
+        return true;
+      }
+
+      // For Safari, we have an older flag which only applies to this one
+      // browser:
+      if (Platform.isApple()) {
+        return this.config_.streaming.useNativeHlsOnSafari;
+      }
+
+      // In all other cases, we prefer MediaSource.
+      return false;
     }
 
     // Unless there are good reasons to use src= (single-file playback or native

lib/util/player_configuration.js

@@ -137,6 +137,7 @@ shaka.util.PlayerConfiguration = class {
       lowLatencyMode: false,
       autoLowLatencyMode: false,
       forceHTTPS: false,
+      preferNativeHls: false,
     };
 
     // WebOS, Tizen, and Chromecast have long hardware pipelines that respond