Remove tons of OILPAN.

sky/engine/core/editing/UndoStack.cpp

 /*
  * Copyright (C) 2006, 2007 Apple, Inc.  All rights reserved.
  * Copyright (C) 2012 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 102 matching lines @@
         RefPtr<UndoStep> step(back->get());
         m_redoStack.remove(back);
 
         ASSERT(!m_inRedo);
         TemporaryChange<bool> redoScope(m_inRedo, true);
         step->reapply();
         // reapply will call us back to push this command onto the undo stack.
     }
 }
 
-void UndoStack::trace(Visitor* visitor)
-{
-    visitor->trace(m_undoStack);
-    visitor->trace(m_redoStack);
-}
-
 } // namespace blink