Implement AudioTrack, AudioTrackList, VideoTrack, and VideoTrackList

public/platform/WebMediaPlayer.h

Index: public/platform/WebMediaPlayer.h
diff --git a/public/platform/WebMediaPlayer.h b/public/platform/WebMediaPlayer.h
index f329a926cbd2d1f578f8e096dd792256239171bb..f74c8ac7e6a51d55b17045f4b4ebd844749a7794 100644
--- a/public/platform/WebMediaPlayer.h
+++ b/public/platform/WebMediaPlayer.h
@@ -48,6 +48,8 @@ struct WebRect;
 struct WebSize;
 class WebGraphicsContext3D;
 
+typedef unsigned WebTrackId;

[acolwell GONE FROM CHROMIUM, 2014/05/16 19:47:56]

nit: I'm a little nervous about putting this in the global Blink namespace. How
about moving this to WebMediaPlayer::TrackId?

+
 class WebMediaPlayer {
 public:
     enum NetworkState {
@@ -162,6 +164,9 @@ public:
     virtual void exitFullscreen() { }
     // Returns true if the player can enter fullscreen.
     virtual bool canEnterFullscreen() const { return false; }
+
+    virtual void enabledAudioTracksChanged(const WebVector<WebTrackId>& enabledTrackIds) { }
+    virtual void selectedVideoTrackChanged(WebTrackId* selectedTrackId) { }

[acolwell GONE FROM CHROMIUM, 2014/05/16 19:47:56]

docs.

[landell, 2014/05/19 13:50:28]

Yes, I am especially interested to know why this is a pointer. For instance,
could this be NULL and what would that mean?

[philipj_slow, 2014/05/19 14:06:45]

I had to find a way to say that no video track at all is selected, which the DOM
API makes possible. For the audio tracks that's an empty list, but for video the
backend needs to be given 0 or 1 tracks, and this is one way of doing it.

Other than the lack of documentation, does this seem OK?

 };
 
 } // namespace blink