Enable Oilpan by default for webaudio/

Source/modules/webaudio/AudioProcessingEvent.h

Index: Source/modules/webaudio/AudioProcessingEvent.h
diff --git a/Source/modules/webaudio/AudioProcessingEvent.h b/Source/modules/webaudio/AudioProcessingEvent.h
index 1e5911d24cf4fe7636aee89090e06fffadb5b5c8..a19d91bc336121a23ccc0f8d2531a223f1a44f48 100644
--- a/Source/modules/webaudio/AudioProcessingEvent.h
+++ b/Source/modules/webaudio/AudioProcessingEvent.h
@@ -37,7 +37,7 @@ class AudioBuffer;
 class AudioProcessingEvent FINAL : public Event {
 public:
     static PassRefPtrWillBeRawPtr<AudioProcessingEvent> create();
-    static PassRefPtrWillBeRawPtr<AudioProcessingEvent> create(PassRefPtrWillBeRawPtr<AudioBuffer> inputBuffer, PassRefPtrWillBeRawPtr<AudioBuffer> outputBuffer, double playbackTime);
+    static PassRefPtrWillBeRawPtr<AudioProcessingEvent> create(AudioBuffer* inputBuffer, AudioBuffer* outputBuffer, double playbackTime);
 
     virtual ~AudioProcessingEvent();
 
@@ -51,10 +51,10 @@ public:
 
 private:
     AudioProcessingEvent();
-    AudioProcessingEvent(PassRefPtrWillBeRawPtr<AudioBuffer> inputBuffer, PassRefPtrWillBeRawPtr<AudioBuffer> outputBuffer, double playbackTime);
+    AudioProcessingEvent(AudioBuffer* inputBuffer, AudioBuffer* outputBuffer, double playbackTime);
 
-    RefPtrWillBeMember<AudioBuffer> m_inputBuffer;
-    RefPtrWillBeMember<AudioBuffer> m_outputBuffer;
+    PersistentWillBeMember<AudioBuffer> m_inputBuffer;
+    PersistentWillBeMember<AudioBuffer> m_outputBuffer;
     double m_playbackTime;
 };