Add SourceBuffer implementations of Audio/VideoTracks

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

+// 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.
+
+#include "modules/mediasource/VideoTrackSourceBuffer.h"
+
+#include "core/html/track/VideoTrack.h"
+#include "modules/mediasource/SourceBuffer.h"
+
+namespace blink {
+
+VideoTrackSourceBuffer::VideoTrackSourceBuffer(SourceBuffer* sourceBuffer)
+    : m_sourceBuffer(sourceBuffer)
+{
+}
+
+VideoTrackSourceBuffer::~VideoTrackSourceBuffer()
+{
+}
+
+const char* VideoTrackSourceBuffer::supplementName()
+{
+    return "VideoTrackSourceBuffer";
+}
+
+VideoTrackSourceBuffer& VideoTrackSourceBuffer::from(VideoTrack& track)
+{
+    VideoTrackSourceBuffer* supplement = static_cast<VideoTrackSourceBuffer*>(HeapSupplement<VideoTrack>::from(track, supplementName()));
+    if (!supplement) {
+        supplement = new VideoTrackSourceBuffer(nullptr);
+        provideTo(track, supplementName(), supplement);
+    }
+    return *supplement;
+}
+
+// static
+SourceBuffer* VideoTrackSourceBuffer::sourceBuffer(VideoTrack& track)
+{
+    return VideoTrackSourceBuffer::from(track).m_sourceBuffer;
+}
+
+
+DEFINE_TRACE(VideoTrackSourceBuffer)
+{
+    visitor->trace(m_sourceBuffer);
+    HeapSupplement<VideoTrack>::trace(visitor);
+}
+
+} // namespace blink
+