Add SourceBuffer implementations of Audio/VideoTracks

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

Index: third_party/WebKit/Source/modules/mediasource/SourceBufferTrackBaseSupplement.h
diff --git a/third_party/WebKit/Source/modules/mediasource/SourceBufferTrackBaseSupplement.h b/third_party/WebKit/Source/modules/mediasource/SourceBufferTrackBaseSupplement.h
new file mode 100644
index 0000000000000000000000000000000000000000..e2ef6b7154685d09c7d714d774d8cbb5d1d18420
--- /dev/null
+++ b/third_party/WebKit/Source/modules/mediasource/SourceBufferTrackBaseSupplement.h
@@ -0,0 +1,34 @@
+// 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 SourceBuffer* sourceBuffer(TrackBase&);
+    static void setSourceBuffer(TrackBase&, SourceBuffer*);
+
+    DECLARE_VIRTUAL_TRACE();
+
+private:
+    static SourceBufferTrackBaseSupplement& from(TrackBase&);
+    static SourceBufferTrackBaseSupplement* fromIfExists(TrackBase&);
+
+    Member<SourceBuffer> m_sourceBuffer;
+};
+
+} // namespace blink
+
+#endif
+