Initial implementation of 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/TrackBaseList.h"
+
+namespace WebCore {
+
+class AudioTrack;
+class HTMLMediaElement;
+
+class AudioTrackList FINAL : public TrackBaseList, public ScriptWrappable {
+public:
+    static PassRefPtrWillBeRawPtr<AudioTrackList> create(HTMLMediaElement*);
+
+    virtual ~AudioTrackList();
+
+    AudioTrack* anonymousIndexedGetter(unsigned index) const;

[philipj_slow, 2014/03/09 09:04:14]

How about making TrackBaseList a template and saying "AudioTrackList :
TrackBaseList<AudioTrack>", would that remove the need for this?

+    AudioTrack* getTrackById(const AtomicString& id) const;
+
+    bool hasEnabledTrack() const;

[philipj_slow, 2014/03/09 09:04:14]

Don't forget to remove this if you remove
HTMLMediaElement::selectInitialTracksIfNecessary().

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