Disallow cross-thread Persistent<> read access.

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

 /*
  * Copyright (C) 2011, 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 52 matching lines @@
 PassRefPtr<MediaElementAudioSourceHandler>
 MediaElementAudioSourceHandler::create(AudioNode& node,
                                        HTMLMediaElement& mediaElement) {
   return adoptRef(new MediaElementAudioSourceHandler(node, mediaElement));
 }
 
 MediaElementAudioSourceHandler::~MediaElementAudioSourceHandler() {
   uninitialize();
 }
 
+HTMLMediaElement* MediaElementAudioSourceHandler::mediaElement() const {
+  return m_mediaElement.get();
+}
+
 void MediaElementAudioSourceHandler::dispose() {
   m_mediaElement->setAudioSourceNode(nullptr);
   AudioHandler::dispose();
 }
 
 void MediaElementAudioSourceHandler::setFormat(size_t numberOfChannels,
                                                float sourceSampleRate) {
   if (numberOfChannels != m_sourceNumberOfChannels ||
       sourceSampleRate != m_sourceSampleRate) {
     if (!numberOfChannels ||
@@ skipping 212 matching lines @@
 
 void MediaElementAudioSourceNode::lock() {
   mediaElementAudioSourceHandler().lock();
 }
 
 void MediaElementAudioSourceNode::unlock() {
   mediaElementAudioSourceHandler().unlock();
 }
 
 }  // namespace blink