Oilpan: Use transition types for HTMLMediaElement and make AudioSourceProviderClient a GC mixin.

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 45 matching lines @@
     // Default to stereo. This could change depending on what the media element .src is set to.
     addOutput(adoptPtr(new AudioNodeOutput(this, 2)));
 
     setNodeType(NodeTypeMediaElementAudioSource);
 
     initialize();
 }
 
 MediaElementAudioSourceNode::~MediaElementAudioSourceNode()
 {
+#if !ENABLE(OILPAN)
     m_mediaElement->setAudioSourceNode(0);
+#endif
     uninitialize();
 }
 
 void MediaElementAudioSourceNode::setFormat(size_t numberOfChannels, float sourceSampleRate)
 {
     if (numberOfChannels != m_sourceNumberOfChannels || sourceSampleRate != m_sourceSampleRate) {
         if (!numberOfChannels || numberOfChannels > AudioContext::maxNumberOfChannels() || sourceSampleRate < minSampleRate || sourceSampleRate > maxSampleRate) {
             // process() will generate silence for these uninitialized values.
             WTF_LOG(Media, "MediaElementAudioSourceNode::setFormat(%u, %f) - unhandled format change", static_cast<unsigned>(numberOfChannels), sourceSampleRate);
             m_sourceNumberOfChannels = 0;
@@ skipping 64 matching lines @@
     ref();
     m_processLock.lock();
 }
 
 void MediaElementAudioSourceNode::unlock()
 {
     m_processLock.unlock();
     deref();
 }
 
+void MediaElementAudioSourceNode::trace(Visitor* visitor)
+{
+    visitor->trace(m_mediaElement);
+    AudioSourceNode::trace(visitor);
+    AudioSourceProviderClient::trace(visitor);
+}
+
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)