Oilpan: have xml/ objects on the heap by default.

Source/core/xml/XPathNSResolver.h

 /*
  * Copyright 2005 Frerich Raabe <raabe@kde.org>
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * 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.
@@ skipping 12 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef XPathNSResolver_h
 #define XPathNSResolver_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
-#include "wtf/RefCounted.h"
 
 namespace blink {
 
-class XPathNSResolver : public RefCountedWillBeGarbageCollectedFinalized<XPathNSResolver>, public ScriptWrappable {
-    DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(XPathNSResolver);
+class XPathNSResolver : public GarbageCollectedFinalized<XPathNSResolver>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
     virtual AtomicString lookupNamespaceURI(const String& prefix) = 0;
 
     DEFINE_INLINE_VIRTUAL_TRACE() { }
 
 protected:
     XPathNSResolver() { }
 };
 
 } // namespace blink
 
 #endif // XPathNSResolver_h