Oilpan: Enable oilpan for callback classes

Source/modules/webaudio/AsyncAudioDecoder.h

Index: Source/modules/webaudio/AsyncAudioDecoder.h
diff --git a/Source/modules/webaudio/AsyncAudioDecoder.h b/Source/modules/webaudio/AsyncAudioDecoder.h
index 93d2fbcbf417a08380aa94ddd695ce4b0a178254..3187b4627fcdf0ffac2b3aecc6ec4c7665aede09 100644
--- a/Source/modules/webaudio/AsyncAudioDecoder.h
+++ b/Source/modules/webaudio/AsyncAudioDecoder.h
@@ -46,7 +46,7 @@ public:
     ~AsyncAudioDecoder();
 
     // Must be called on the main thread.
-    void decodeAsync(ArrayBuffer* audioData, float sampleRate, PassOwnPtrWillBeRawPtr<AudioBufferCallback> successCallback, PassOwnPtrWillBeRawPtr<AudioBufferCallback> errorCallback);
+    void decodeAsync(ArrayBuffer* audioData, float sampleRate, AudioBufferCallback* successCallback, AudioBufferCallback* errorCallback);
 
 private:
     AudioBuffer* createAudioBufferFromAudioBus(AudioBus*);