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

Source/core/html/HTMLMediaElement.idl

 /*
  * Copyright (C) 2007, 2010, 2011, 2012 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 63 matching lines @@
     [Reflect] attribute DOMString mediaGroup;
     [StrictTypeChecking] attribute MediaController controller;
 
     // controls
     attribute boolean controls;
     [RaisesException=Setter] attribute double volume;
     attribute boolean muted;
     [Reflect=muted] attribute boolean defaultMuted;
 
     // tracks
+    [RuntimeEnabled=AudioVideoTracks] readonly attribute AudioTrackList audioTracks;
+    [RuntimeEnabled=AudioVideoTracks] readonly attribute VideoTrackList videoTracks;
     [RuntimeEnabled=VideoTrack] readonly attribute TextTrackList textTracks;
     [RuntimeEnabled=VideoTrack, RaisesException] TextTrack addTextTrack(DOMString kind, optional DOMString label, optional DOMString language);
 
     // WebKit extensions
 
     // The number of bytes consumed by the media decoder.
     [MeasureAs=PrefixedAudioDecodedByteCount] readonly attribute unsigned long webkitAudioDecodedByteCount;
     [MeasureAs=PrefixedVideoDecodedByteCount] readonly attribute unsigned long webkitVideoDecodedByteCount;
 };