Initial implementation of AudioTrack, AudioTrackList, VideoTrack, and VideoTrackList.

public/platform/WebMediaPlayer.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 144 matching lines @@
     virtual void setContentDecryptionModule(WebContentDecryptionModule* cdm) { }
 
     // Sets the poster image URL.
     virtual void setPoster(const WebURL& poster) { }
 
     // Instruct WebMediaPlayer to enter/exit fullscreen.
     virtual void enterFullscreen() { }
     virtual void exitFullscreen() { }
     // Returns true if the player can enter fullscreen.
     virtual bool canEnterFullscreen() const { return false; }
+
+    virtual void enabledAudioTracksChanged(const WebVector<WebString>& enabledTrackIDs) { }
+    virtual void selectedVideoTrackChanged(const WebString& selectedTrackID) { }
 };
 
 } // namespace blink
 
 #endif