Oilpan: Allocate all EventTarget derived types on the manged heap.

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 e0a95c074a8cdc6da7bf5b536a6a89138223c6e9..b1fa711671113b30fb17dac1c120f960f74ab6b4 100644
--- a/Source/modules/webaudio/AudioNode.h
+++ b/Source/modules/webaudio/AudioNode.h
@@ -52,6 +52,7 @@ class ExceptionState;
 
 // AudioNode has its own ref-counting mechanism that use RefTypes so we cannot use RefCountedGarbageCollected.
 class AudioNode : public NoBaseWillBeGarbageCollectedFinalized<AudioNode>, public ScriptWrappable, public EventTargetWithInlineData {
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(AudioNode);
 public:
     enum { ProcessingSizeInFrames = 128 };
 
@@ -180,7 +181,7 @@ public:
     virtual const AtomicString& interfaceName() const OVERRIDE FINAL;
     virtual ExecutionContext* executionContext() const OVERRIDE FINAL;
 
-    virtual void trace(Visitor*);
+    virtual void trace(Visitor*) OVERRIDE;
 
 #if ENABLE(OILPAN)
     void clearKeepAlive();