Add SourceBuffer implementations of Audio/VideoTracks

third_party/WebKit/Source/modules/mediasource/VideoTrackSourceBuffer.h

+// Copyright 2016 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 VideoTrackSourceBuffer_h
+#define VideoTrackSourceBuffer_h
+
+#include "modules/mediasource/SourceBufferTrackBaseSupplement.h"
+
+namespace blink {
+
+class SourceBuffer;
+class VideoTrack;
+
+class VideoTrackSourceBuffer final : public SourceBufferTrackBaseSupplement {
+public:
+    explicit VideoTrackSourceBuffer(VideoTrack&, SourceBuffer*);
+};
+
+} // namespace blink
+
+#endif