Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/core/css/DOMWindowCSS.h

 /*
  * Copyright (C) 2012 Motorola Mobility 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
@@ skipping 20 matching lines @@
 #define DOMWindowCSS_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 
 namespace blink {
 
-class DOMWindowCSS : public RefCountedWillBeGarbageCollected<DOMWindowCSS>, public ScriptWrappable {
+class DOMWindowCSS : public GarbageCollected<DOMWindowCSS>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static bool supports(const String& property, const String& value);
     static bool supports(const String& conditionText);
     static String escape(const String& ident);
 
     DEFINE_INLINE_TRACE() { }
 
 private:
     DOMWindowCSS() { }
 };
 
 } // namespace blink
 
 #endif