Oilpan: move DOMImplementation to the 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 5661 matching lines @@
                 deadNodes.append(it->key);
         }
         for (unsigned i = 0; i < deadNodes.size(); ++i)
             didClearTouchEventHandlers(deadNodes[i]);
     }
 }
 
 void Document::trace(Visitor* visitor)
 {
     visitor->trace(m_docType);
+    visitor->trace(m_implementation);
     visitor->trace(m_autofocusElement);
     visitor->trace(m_focusedElement);
     visitor->trace(m_hoverNode);
     visitor->trace(m_activeHoverElement);
     visitor->trace(m_documentElement);
     visitor->trace(m_titleElement);
     visitor->trace(m_currentScriptStack);
     visitor->trace(m_transformSourceDocument);
     visitor->trace(m_cssCanvasElements);
     visitor->trace(m_topLayerElements);
     visitor->trace(m_elemSheet);
     visitor->trace(m_styleEngine);
     visitor->trace(m_fetcher);
     visitor->trace(m_contextFeatures);
     visitor->trace(m_styleSheetList);
     visitor->trace(m_mediaQueryMatcher);
     visitor->trace(m_associatedFormControls);
     visitor->trace(m_templateDocument);
     visitor->trace(m_templateDocumentHost);
     visitor->trace(m_visibilityObservers);
     visitor->trace(m_userActionElements);
     visitor->registerWeakMembers<Document, &Document::clearWeakMembers>(this);
     DocumentSupplementable::trace(visitor);
     TreeScope::trace(visitor);
     ContainerNode::trace(visitor);
     ExecutionContext::trace(visitor);
 }
 
 } // namespace WebCore