Oilpan: extend tracing over WebFrame trees.

Source/web/WebLocalFrameImpl.h

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 295 matching lines @@
 
     // Invalidates vertical scrollbar only.
     void invalidateScrollbar() const;
 
     // Invalidates both content area and the scrollbar.
     void invalidateAll() const;
 
     // Returns a hit-tested VisiblePosition for the given point
     VisiblePosition visiblePositionForWindowPoint(const WebPoint&);
 
+#if ENABLE(OILPAN)
     void trace(Visitor*);
+#endif
 
 private:
     friend class FrameLoaderClientImpl;
 
     explicit WebLocalFrameImpl(WebFrameClient*);
 
     // Sets the local core frame and registers destruction observers.
     void setCoreFrame(PassRefPtrWillBeRawPtr<LocalFrame>);
 
     void loadJavaScriptURL(const KURL&);
@@ skipping 36 matching lines @@
     GC_PLUGIN_IGNORE("340522")
     Persistent<WebLocalFrameImpl> m_selfKeepAlive;
 #endif
 };
 
 DEFINE_TYPE_CASTS(WebLocalFrameImpl, WebFrame, frame, frame->isWebLocalFrame(), frame.isWebLocalFrame());
 
 } // namespace blink
 
 #endif