Move CSSRuleList to the garbage collected heap

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 538 matching lines @@
         m_styleSheetList->detachFromDocument();
 
     if (m_import) {
         m_import->wasDetachedFromDocument();
         m_import = 0;
     }
 
     m_timeline->detachFromDocument();
     m_transitionTimeline->detachFromDocument();
 
-    m_styleEngine.clear(); // We need to destory CSSFontSelector before destroying m_fetcher.
+    // We need to destroy CSSFontSelector before destroying m_fetcher.
+    if (m_styleEngine)
+        m_styleEngine->detachFromDocument();
 
     if (m_elemSheet)
         m_elemSheet->clearOwnerNode();
 
     // It's possible for multiple Documents to end up referencing the same ResourceFetcher (e.g., SVGImages
     // load the initial empty document and the SVGDocument with the same DocumentLoader).
     if (m_fetcher->document() == this)
         m_fetcher->setDocument(0);
     m_fetcher.clear();
 
@@ skipping 4914 matching lines @@
 }
 
 void Document::invalidateNodeListCaches(const QualifiedName* attrName)
 {
     HashSet<LiveNodeListBase*>::iterator end = m_listsInvalidatedAtDocument.end();
     for (HashSet<LiveNodeListBase*>::iterator it = m_listsInvalidatedAtDocument.begin(); it != end; ++it)
         (*it)->invalidateCache(attrName);
 }
 
 } // namespace WebCore