Implement AudioTrack, AudioTrackList, VideoTrack, and VideoTrackList

Source/core/html/track/AudioTrackList.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef AudioTrackList_h
+#define AudioTrackList_h
+
+#include "bindings/v8/ScriptWrappable.h"
+#include "core/html/track/AudioTrack.h"
+#include "core/html/track/TrackListBase.h"
+
+namespace WebCore {
+
+class AudioTrackList FINAL : public TrackListBase<AudioTrack>, public ScriptWrappable {
+public:
+    static PassRefPtr<AudioTrackList> create(HTMLMediaElement&);

[sof, 2014/05/22 11:47:36]

Change return type to PassRefPtrWillBeRawPtr<AudioTrackList>

+
+    virtual ~AudioTrackList();
+
+    bool hasEnabledTrack() const;
+
+    // EventTarget
+    virtual const AtomicString& interfaceName() const OVERRIDE;
+
+private:
+    explicit AudioTrackList(HTMLMediaElement&);
+};
+
+}
+
+#endif