Implement disabling and enabling media tracks

media/blink/webmediaplayer_impl.h

Index: media/blink/webmediaplayer_impl.h
diff --git a/media/blink/webmediaplayer_impl.h b/media/blink/webmediaplayer_impl.h
index 9a127640bbf5fa8b6c1d4909d4c6ea2b7a5c724b..9d6fcfa052fc3b94ea8084d44bed9c5768bae791 100644
--- a/media/blink/webmediaplayer_impl.h
+++ b/media/blink/webmediaplayer_impl.h
@@ -129,6 +129,12 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   bool hasVideo() const override;
   bool hasAudio() const override;
 
+  void enabledAudioTracksChanged(
+      const blink::WebVector<blink::WebMediaPlayer::TrackId>& enabledTrackIds)
+      override;
+  void selectedVideoTrackChanged(
+      blink::WebMediaPlayer::TrackId* selectedTrackId) override;
+
   // Dimensions of the video.
   blink::WebSize naturalSize() const override;