Remove tons of OILPAN.

sky/engine/core/html/canvas/CanvasContextAttributes.h

 /*
  * 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:
  *     * 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
  * copyright notice, this list of conditions and the following disclaimer
@@ skipping 20 matching lines @@
 #include "wtf/RefCounted.h"
 
 namespace blink {
 
 // A base class for any attributes that are needed which would affect
 // the creation of the Canvas's rendering context.
 
 class CanvasContextAttributes : public RefCounted<CanvasContextAttributes> {
     DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(CanvasContextAttributes);
 public:
-    virtual void trace(Visitor*) { }
 
 protected:
     CanvasContextAttributes();
 };
 
 } // namespace blink
 
 #endif // CanvasContextAttributes_h