Oilpan: A thread that is not attached to Oilpan shouldn't create a CrossThreadPersistent

Source/modules/webaudio/ScriptProcessorNode.cpp

 /*
  * Copyright (C) 2010, 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 20 matching lines @@
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/CrossThreadTask.h"
 #include "core/dom/ExecutionContext.h"
 #include "modules/webaudio/AudioBuffer.h"
 #include "modules/webaudio/AudioContext.h"
 #include "modules/webaudio/AudioNodeInput.h"
 #include "modules/webaudio/AudioNodeOutput.h"
 #include "modules/webaudio/AudioProcessingEvent.h"
 #include "public/platform/Platform.h"
 #include "wtf/Float32Array.h"
+#include "wtf/UnretainedPtr.h"
 
 namespace blink {
 
 static size_t chooseBufferSize()
 {
     // Choose a buffer size based on the audio hardware buffer size. Arbitarily make it a power of
     // two that is 4 times greater than the hardware buffer size.
     // FIXME: What is the best way to choose this?
     size_t hardwareBufferSize = Platform::current()->audioHardwareBufferSize();
     size_t bufferSize = 1 << static_cast<unsigned>(log2(4 * hardwareBufferSize) + 0.5);
@@ skipping 172 matching lines @@
         // This could be a problem if the main thread is very busy doing other things and is being held up handling previous requests.
         // The audio thread can't block on this lock, so we call tryLock() instead.
         MutexTryLocker tryLocker(m_processEventLock);
         if (!tryLocker.locked()) {
             // We're late in handling the previous request. The main thread must be very busy.
             // The best we can do is clear out the buffer ourself here.
             outputBuffer->zero();
         } else if (context()->executionContext()) {
             // Fire the event on the main thread, not this one (which is the realtime audio thread).
             m_doubleBufferIndexForEvent = m_doubleBufferIndex;
-            context()->executionContext()->postTask(createCrossThreadTask(&ScriptProcessorNode::fireProcessEvent, this));
+            context()->executionContext()->postTask(createCrossThreadTask(&ScriptProcessorNode::fireProcessEvent, UnretainedPtr<ScriptProcessorNode>(this)));
         }
 
         swapBuffers();
     }
 }
 
 void ScriptProcessorNode::fireProcessEvent()
 {
     ASSERT(isMainThread());
 
@@ skipping 59 matching lines @@
 void ScriptProcessorNode::trace(Visitor* visitor)
 {
     visitor->trace(m_inputBuffers);
     visitor->trace(m_outputBuffers);
     AudioNode::trace(visitor);
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)