Add SourceBuffer implementations of Audio/VideoTracks

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