Oilpan: Remove Persistent handles from heap allocated CSSRule objects and fix finalization of CSSKe…

Source/core/css/CSSImportRule.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006, 2008, 2009, 2010, 2012 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.
  *
@@ skipping 73 matching lines @@
         m_styleSheetCSSOMWrapper = CSSStyleSheet::create(m_importRule->styleSheet(), const_cast<CSSImportRule*>(this));
     return m_styleSheetCSSOMWrapper.get();
 }
 
 void CSSImportRule::reattach(StyleRuleBase*)
 {
     // FIXME: Implement when enabling caching for stylesheets with import rules.
     ASSERT_NOT_REACHED();
 }
 
+void CSSImportRule::trace(Visitor* visitor)
+{
+    visitor->trace(m_importRule);
+    CSSRule::trace(visitor);
+}
+
 } // namespace WebCore