Oilpan: Remove GC_INFO_{DEFINE,DECLARE} macros

Source/core/xml/XMLSerializer.cpp

 /*
  *  Copyright (C) 2003, 2006 Apple Inc. All rights reserved.
  *  Copyright (C) 2006 Samuel Weinig (sam@webkit.org)
  *  Copyright (C) 2013 Samsung Electronics. All rights reserved.
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
@@ skipping 11 matching lines @@
 #include "core/xml/XMLSerializer.h"
 
 #include "bindings/v8/ExceptionState.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/editing/markup.h"
 #include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
-DEFINE_GC_INFO(XMLSerializer);
-
 String XMLSerializer::serializeToString(Node* node, ExceptionState& exceptionState)
 {
     if (!node) {
         exceptionState.throwDOMException(TypeError, "Invalid node value.");
         return String();
     }
 
     return createMarkup(node);
 }
 
 } // namespace WebCore