Simplify MediaStreamAudioSourceNode ownerships.

third_party/WebKit/Source/modules/webaudio/MediaStreamAudioSourceNode.cpp

 /*
  * Copyright (C) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 18 matching lines @@
 #include "modules/webaudio/AudioNodeOutput.h"
 #include "modules/webaudio/BaseAudioContext.h"
 #include "modules/webaudio/MediaStreamAudioSourceOptions.h"
 #include "wtf/Locker.h"
 #include <memory>
 
 namespace blink {
 
 MediaStreamAudioSourceHandler::MediaStreamAudioSourceHandler(
     AudioNode& node,
-    MediaStream& mediaStream,
-    MediaStreamTrack* audioTrack,
     std::unique_ptr<AudioSourceProvider> audioSourceProvider)
     : AudioHandler(NodeTypeMediaStreamAudioSource,
                    node,
                    node.context()->sampleRate()),
-      m_mediaStream(mediaStream),
-      m_audioTrack(audioTrack),
       m_audioSourceProvider(std::move(audioSourceProvider)),
       m_sourceNumberOfChannels(0) {
   // Default to stereo. This could change depending on the format of the
   // MediaStream's audio track.
   addOutput(2);
 
   initialize();
 }
 
 PassRefPtr<MediaStreamAudioSourceHandler> MediaStreamAudioSourceHandler::create(
     AudioNode& node,
-    MediaStream& mediaStream,
-    MediaStreamTrack* audioTrack,
     std::unique_ptr<AudioSourceProvider> audioSourceProvider) {
-  return adoptRef(new MediaStreamAudioSourceHandler(
-      node, mediaStream, audioTrack, std::move(audioSourceProvider)));
+  return adoptRef(
+      new MediaStreamAudioSourceHandler(node, std::move(audioSourceProvider)));
 }
 
 MediaStreamAudioSourceHandler::~MediaStreamAudioSourceHandler() {
   uninitialize();
 }
 
 void MediaStreamAudioSourceHandler::setFormat(size_t numberOfChannels,
                                               float sourceSampleRate) {
   if (numberOfChannels != m_sourceNumberOfChannels ||
       sourceSampleRate != context()->sampleRate()) {
@@ skipping 24 matching lines @@
 }
 
 void MediaStreamAudioSourceHandler::process(size_t numberOfFrames) {
   AudioBus* outputBus = output(0).bus();
 
   if (!getAudioSourceProvider()) {
     outputBus->zero();
     return;
   }
 
-  if (!getMediaStream() ||
-      m_sourceNumberOfChannels != outputBus->numberOfChannels()) {
+  if (m_sourceNumberOfChannels != outputBus->numberOfChannels()) {
     outputBus->zero();
     return;
   }
 
   // Use a tryLock() to avoid contention in the real-time audio thread.
   // If we fail to acquire the lock then the MediaStream must be in the middle
   // of a format change, so we output silence in this case.
   MutexTryLocker tryLocker(m_processLock);
   if (tryLocker.locked()) {
     getAudioSourceProvider()->provideInput(outputBus, numberOfFrames);
   } else {
     // We failed to acquire the lock.
     outputBus->zero();
   }
 }
 
 // ----------------------------------------------------------------
 
 MediaStreamAudioSourceNode::MediaStreamAudioSourceNode(
     BaseAudioContext& context,
     MediaStream& mediaStream,
     MediaStreamTrack* audioTrack,
     std::unique_ptr<AudioSourceProvider> audioSourceProvider)
-    : AudioNode(context) {
+    : AudioNode(context), m_audioTrack(audioTrack), m_mediaStream(mediaStream) {
   setHandler(MediaStreamAudioSourceHandler::create(
-      *this, mediaStream, audioTrack, std::move(audioSourceProvider)));
+      *this, std::move(audioSourceProvider)));
 }
 
 MediaStreamAudioSourceNode* MediaStreamAudioSourceNode::create(
     BaseAudioContext& context,
     MediaStream& mediaStream,
     ExceptionState& exceptionState) {
   DCHECK(isMainThread());
 
   if (context.isContextClosed()) {
     context.throwExceptionForClosedState(exceptionState);
@@ skipping 28 matching lines @@
 }
 
 MediaStreamAudioSourceNode* MediaStreamAudioSourceNode::create(
     BaseAudioContext* context,
     const MediaStreamAudioSourceOptions& options,
     ExceptionState& exceptionState) {
   return create(*context, *options.mediaStream(), exceptionState);
 }
 
 DEFINE_TRACE(MediaStreamAudioSourceNode) {
+  visitor->trace(m_audioTrack);
+  visitor->trace(m_mediaStream);
   AudioSourceProviderClient::trace(visitor);
   AudioNode::trace(visitor);
 }
 
 MediaStreamAudioSourceHandler&
 MediaStreamAudioSourceNode::mediaStreamAudioSourceHandler() const {
   return static_cast<MediaStreamAudioSourceHandler&>(handler());
 }
 
 MediaStream* MediaStreamAudioSourceNode::getMediaStream() const {
-  return mediaStreamAudioSourceHandler().getMediaStream();
+  return m_mediaStream;
 }
 
 void MediaStreamAudioSourceNode::setFormat(size_t numberOfChannels,
                                            float sourceSampleRate) {
   mediaStreamAudioSourceHandler().setFormat(numberOfChannels, sourceSampleRate);
 }
 
 }  // namespace blink