Oilpan: avoid invoking some no-op finalizers.

Source/core/css/StyleSheetList.cpp

 /**
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 18 matching lines @@
 
 namespace blink {
 
 using namespace HTMLNames;
 
 StyleSheetList::StyleSheetList(TreeScope* treeScope)
     : m_treeScope(treeScope)
 {
 }
 
-StyleSheetList::~StyleSheetList()
-{
-}
+DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(StyleSheetList);
 
 inline const WillBeHeapVector<RefPtrWillBeMember<StyleSheet> >& StyleSheetList::styleSheets()
 {
 #if !ENABLE(OILPAN)
     if (!m_treeScope)
         return m_detachedStyleSheets;
 #endif
     return document()->styleEngine()->styleSheetsForStyleSheetList(*m_treeScope);
 }
 
@@ skipping 40 matching lines @@
         return 0;
     return item->sheet();
 }
 
 void StyleSheetList::trace(Visitor* visitor)
 {
     visitor->trace(m_treeScope);
 }
 
 } // namespace blink