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..b7fc5b9a301dabffad797bf98428449db93fc578 100644
--- a/Source/modules/webaudio/AudioNode.h
+++ b/Source/modules/webaudio/AudioNode.h
@@ -50,7 +50,7 @@ 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 {
+class AudioNode : public GarbageCollectedFinalized<AudioNode>, public ScriptWrappable, public EventTargetWithInlineData {

[Mads Ager (chromium), 2014/03/20 08:30:00]

We don't want to move this into the oilpan heap when !ENABLE(OILPAN), therefore,
this should be public NoBaseWillBeGarbageCollectedFinalized.

[keishi, 2014/03/27 07:39:37]

Done.

 public:
     enum { ProcessingSizeInFrames = 128 };
 
@@ -179,6 +179,10 @@ public:
     virtual const AtomicString& interfaceName() const OVERRIDE FINAL;
     virtual ExecutionContext* executionContext() const OVERRIDE FINAL;
 
+    virtual void trace(Visitor*);
+
+    void clearKeepAlive();
+
 protected:
     // Inputs and outputs must be created before the AudioNode is initialized.
     void addInput(PassOwnPtr<AudioNodeInput>);
@@ -195,11 +199,23 @@ 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;
 
+    // AudioNodes are still reference counted but they are in the
+    // oilpan heap because the ScriptProcessorNode is an EventTarget.
+    // This self-persistent keeps the object from being deleted
+    // until the reference count reaches zero.
+    //
+    // It is safe to drop the self-persistent when the ref count
+    // of a ScriptProcessorNode reaches zero. At that point, the
+    // ScriptProcessor node is removed from the AudioContext and
+    // it cannot be reattached. Therefore, the reference count
+    // will not go above zero again.
+    OwnPtr<Persistent<AudioNode> > m_keepAlive;

[Mads Ager (chromium), 2014/03/20 08:30:00]

This should be guarded with #if ENABLE(OILPAN)

+
     double m_lastProcessingTime;
     double m_lastNonSilentTime;