Enable Oilpan by default for webaudio/

Source/core/html/HTMLMediaElement.h

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 574 matching lines @@
     WillBeHeapVector<RefPtrWillBeMember<TextTrack> > m_textTracksWhenResourceSelectionBegan;
 
     CueIntervalTree m_cueTree;
 
     CueList m_currentlyActiveCues;
     int m_ignoreTrackDisplayUpdate;
 
 #if ENABLE(WEB_AUDIO)
     // This is a weak reference, since m_audioSourceNode holds a reference to us.
     // FIXME: Oilpan: Consider making this a strongly traced pointer with oilpan where strong cycles are not a problem.
+    GC_PLUGIN_IGNORE("http://crbug.com/404577")
     RawPtrWillBeWeakMember<AudioSourceProviderClient> m_audioSourceNode;
 #endif
 
     friend class MediaController;
     RefPtrWillBeMember<MediaController> m_mediaController;
 
     friend class Internals;
     friend class TrackDisplayUpdateScope;
 
     static URLRegistry* s_mediaStreamRegistry;
@@ skipping 21 matching lines @@
 inline bool isHTMLMediaElement(const HTMLElement& element)
 {
     return isHTMLAudioElement(element) || isHTMLVideoElement(element);
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 } //namespace
 
 #endif