Add SourceBuffer implementations of Audio/VideoTracks

third_party/WebKit/Source/modules/mediasource/SourceBufferTrackBaseSupplement.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 SourceBufferTrackBaseSupplement_h
+#define SourceBufferTrackBaseSupplement_h
+
+#include "platform/Supplementable.h"
+#include "wtf/Allocator.h"
+
+namespace blink {
+
+class TrackBase;
+class SourceBuffer;
+
+class SourceBufferTrackBaseSupplement : public GarbageCollected<SourceBufferTrackBaseSupplement>, public Supplement<TrackBase> {
+    USING_GARBAGE_COLLECTED_MIXIN(SourceBufferTrackBaseSupplement);
+public:
+    static SourceBufferTrackBaseSupplement& from(TrackBase&);
+
+    static SourceBuffer* sourceBuffer(TrackBase&);
+    void setSourceBuffer(SourceBuffer*);

[philipj_slow, 2016/04/07 08:59:35]

Hmm, it doesn't matter much, but I think it'd look a bit tidier if this were
also static, then clients of the class will only interact with this
getter/setter pair, while from/fromIfExists is internal.

[servolk, 2016/04/07 17:03:55]

Done.

+
+    DECLARE_VIRTUAL_TRACE();
+
+private:
+    explicit SourceBufferTrackBaseSupplement(TrackBase&);
+    Member<SourceBuffer> m_sourceBuffer;
+};
+
+} // namespace blink
+
+#endif
+