Enable Oilpan by default for webaudio/

Source/modules/webaudio/AudioListener.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 38 matching lines @@
 {
     ScriptWrappable::init(this);
 }
 
 AudioListener::~AudioListener()
 {
 }
 
 void AudioListener::trace(Visitor* visitor)
 {
-#if ENABLE(OILPAN)
     visitor->trace(m_panners);
-#endif
 }
 
 void AudioListener::addPanner(PannerNode* panner)
 {
     ASSERT(isMainThread());
     if (!panner)
         return;
 
     m_panners.append(panner);
 }
@@ skipping 93 matching lines @@
 
     // This synchronizes with panner's process().
     MutexLocker listenerLocker(m_listenerLock);
     m_speedOfSound = speedOfSound;
     markPannersAsDirty(PannerNode::DopplerRateDirty);
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)