feat: Add streaming.preferNativeDash config (#7737)

This is useful for WebOS, because in MSE there is no support for VVC but
there is support for src=

Author: avelad

demo/config.js

@@ -488,6 +488,8 @@ shakaDemo.Config = class {
         .addBoolInput_('Force HTTPS', 'streaming.forceHTTPS')
         .addNumberInput_('Min bytes for progress events',
             'streaming.minBytesForProgressEvents')
+        .addBoolInput_('Prefer native DASH playback when available',
+            'streaming.preferNativeDash')
         .addBoolInput_('Prefer native HLS playback when available',
             'streaming.preferNativeHls')
         .addNumberInput_('Update interval seconds',

externs/shaka/player.js

@@ -1564,6 +1564,7 @@ shaka.extern.LiveSyncConfiguration;
  *   forceHTTP: boolean,
  *   forceHTTPS: boolean,
  *   minBytesForProgressEvents: number,
+ *   preferNativeDash: boolean,
  *   preferNativeHls: boolean,
  *   updateIntervalSeconds: number,
  *   observeQualityChanges: boolean,
@@ -1740,6 +1741,10 @@ shaka.extern.LiveSyncConfiguration;
  *   if possible. To avoid issues around feeding ABR with request history, this
  *   value should be greater than or equal to `abr.advanced.minBytes`.
  *   By default equals 16e3 (the same value as `abr.advanced.minBytes`).
+ * @property {boolean} preferNativeDash
+ *   If true, prefer native DASH playback when possible, regardless of platform.
+ *   <br>
+ *   Defaults to <code>false</code>.
  * @property {boolean} preferNativeHls
  *   If true, prefer native HLS playback when possible, regardless of platform.
  *   <br>

lib/player.js

@@ -2371,6 +2371,11 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
         return this.config_.streaming.preferNativeHls;
       }
 
+      if (MimeUtils.isDashType(mimeType)) {
+        // Native DASH can be preferred on any platform via this flag:
+        return this.config_.streaming.preferNativeDash;
+      }
+
       // In all other cases, we prefer MediaSource.
       return false;
     }

lib/util/mime_utils.js

@@ -251,6 +251,17 @@ shaka.util.MimeUtils = class {
         mimeType === 'application/vnd.apple.mpegurl';
   }
 
+  /**
+   * Checks if the given MIME type is DASH MIME type.
+   *
+   * @param {string} mimeType
+   * @return {boolean}
+   */
+  static isDashType(mimeType) {
+    return mimeType === 'application/dash+xml' ||
+        mimeType === 'video/vnd.mpeg.dash.mpd';
+  }
+
   /**
    * Get the base and profile of a codec string. Where [0] will be the codec
    * base and [1] will be the profile.

lib/util/player_configuration.js

@@ -233,6 +233,7 @@ shaka.util.PlayerConfiguration = class {
       forceHTTP: false,
       forceHTTPS: false,
       minBytesForProgressEvents: minBytes,
+      preferNativeDash: false,
       preferNativeHls: false,
       updateIntervalSeconds: 1,
       observeQualityChanges: false,

test/player_unit.js

@@ -731,6 +731,62 @@ describe('Player', () => {
       });
     });
 
+    describe('when config.streaming.preferNativeDash is set to true', () => {
+      beforeAll(() => {
+        shaka.media.ManifestParser.registerParserByMime(
+            'application/dash+xml',
+            () => new shaka.test.FakeManifestParser(manifest));
+      });
+
+      afterAll(() => {
+        // IMPORTANT: restore the ORIGINAL parser.  DO NOT just unregister the
+        // fake!
+        shaka.media.ManifestParser.registerParserByMime(
+            'application/dash+xml',
+            () => new shaka.dash.DashParser());
+      });
+
+      afterEach(() => {
+        video.canPlayType.calls.reset();
+      });
+
+      it('only applies to DASH streams', async () => {
+        video.canPlayType.and.returnValue('maybe');
+        spyOn(shaka.util.Platform, 'anyMediaElement').and.returnValue(video);
+        spyOn(shaka.util.Platform, 'supportsMediaSource').and.returnValue(true);
+        // Make sure player.load() resolves for src=
+        spyOn(shaka.util.MediaReadyState, 'waitForReadyState').and.callFake(
+            (mediaElement, readyState, eventManager, callback) => {
+              callback();
+            });
+
+        player.configure({
+          streaming: {
+            preferNativeDash: true,
+          },
+        });
+
+        await player.load(fakeManifestUri, undefined, 'application/dash+xml');
+
+        expect(player.getLoadMode()).toBe(shaka.Player.LoadMode.SRC_EQUALS);
+      });
+
+      it('does not apply to non-DASH streams', async () => {
+        video.canPlayType.and.returnValue('maybe');
+        spyOn(shaka.util.Platform, 'supportsMediaSource').and.returnValue(true);
+
+        player.configure({
+          streaming: {
+            preferNativeDash: true,
+          },
+        });
+
+        await player.load(fakeManifestUri, 0, fakeMimeType);
+
+        expect(player.getLoadMode()).toBe(shaka.Player.LoadMode.MEDIA_SOURCE);
+      });
+    });
+
     describe('when config.streaming.preferNativeHls is set to true', () => {
       beforeAll(() => {
         shaka.media.ManifestParser.registerParserByMime(