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

Source/core/html/track/AudioTrackList.cpp

+// 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.
+
+#include "config.h"
+#include "core/html/track/AudioTrackList.h"
+
+namespace WebCore {
+
+PassRefPtr<AudioTrackList> AudioTrackList::create(HTMLMediaElement& mediaElement)
+{
+    return adoptRef(new AudioTrackList(mediaElement));
+}
+
+AudioTrackList::~AudioTrackList()
+{
+}
+
+AudioTrackList::AudioTrackList(HTMLMediaElement& mediaElement)
+    : TrackListBase<AudioTrack>(&mediaElement)
+{
+    ScriptWrappable::init(this);
+}
+
+bool AudioTrackList::hasEnabledTrack() const
+{
+    for (unsigned i = 0; i < length(); ++i) {
+        if (anonymousIndexedGetter(i)->enabled())
+            return true;
+    }
+
+    return false;
+}
+
+const AtomicString& AudioTrackList::interfaceName() const
+{
+    return EventTargetNames::AudioTrackList;
+}
+
+}