Move webaudio to oilpan

Source/modules/webaudio/AudioNode.h

Index: Source/modules/webaudio/AudioNode.h
diff --git a/Source/modules/webaudio/AudioNode.h b/Source/modules/webaudio/AudioNode.h
index 5ebe221ee62803656bb0fb4e6301e83faf4d0502..631514e263ad2a0753de7acc42be1451b3921a00 100644
--- a/Source/modules/webaudio/AudioNode.h
+++ b/Source/modules/webaudio/AudioNode.h
@@ -50,7 +50,8 @@ class ExceptionState;
 // An AudioDestinationNode has one input and no outputs and represents the final destination to the audio hardware.
 // Most processing nodes such as filters will have one input and one output, although multiple inputs and outputs are possible.
 
-class AudioNode : public ScriptWrappable, public EventTargetWithInlineData {
+// AudioNode has its own ref-counting mechanism that use RefTypes so we cannot use RefCountedGarbageCollected.
+class AudioNode : public NoBaseWillBeGarbageCollectedFinalized<AudioNode>, public ScriptWrappable, public EventTargetWithInlineData {
 public:
     enum { ProcessingSizeInFrames = 128 };
 
@@ -179,6 +180,12 @@ public:
     virtual const AtomicString& interfaceName() const OVERRIDE FINAL;
     virtual ExecutionContext* executionContext() const OVERRIDE FINAL;
 
+    virtual void trace(Visitor*);
+
+#if ENABLE(OILPAN)
+    void clearKeepAlive();
+#endif
+
 protected:
     // Inputs and outputs must be created before the AudioNode is initialized.
     void addInput(PassOwnPtr<AudioNodeInput>);
@@ -195,11 +202,23 @@ protected:
 private:
     volatile bool m_isInitialized;
     NodeType m_nodeType;
-    RefPtr<AudioContext> m_context;
+    RefPtrWillBeMember<AudioContext> m_context;
     float m_sampleRate;
     Vector<OwnPtr<AudioNodeInput> > m_inputs;
     Vector<OwnPtr<AudioNodeOutput> > m_outputs;
 
+#if ENABLE(OILPAN)
+    // AudioNodes are in the oilpan heap but they are still reference counted at
+    // the same time. This is because we are not allowed to stop the audio
+    // thread and thus the audio thread cannot allocate objects in the oilpan
+    // heap.
+    // The m_keepAlive handle is used to keep a persistent reference to this
+    // AudioNode while someone has a reference to this AudioNode through a
+    // RefPtr.
+    GC_PLUGIN_IGNORE("http://crbug.com/353083")
+    OwnPtr<Persistent<AudioNode> > m_keepAlive;
+#endif
+
     double m_lastProcessingTime;
     double m_lastNonSilentTime;