Convert DocumentParser code to Use more reference

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 2303 matching lines @@
     ASSERT(topDocument == this || !m_axObjectCache);
     if (!topDocument.m_axObjectCache)
         topDocument.m_axObjectCache = adoptPtr(new AXObjectCache(topDocument));
     return topDocument.m_axObjectCache.get();
 }
 
 PassRefPtr<DocumentParser> Document::createParser()
 {
     if (isHTMLDocument()) {
         bool reportErrors = InspectorInstrumentation::collectingHTMLParseErrors(page());
-        return HTMLDocumentParser::create(toHTMLDocument(this), reportErrors);
+        return HTMLDocumentParser::create(toHTMLDocument(*this), reportErrors);
     }
     // FIXME: this should probably pass the frame instead
     return XMLDocumentParser::create(*this, view());
 }
 
 bool Document::isFrameSet() const
 {
     if (!isHTMLDocument())
         return false;
     return isHTMLFrameSetElement(body());
@@ skipping 3425 matching lines @@
     visitor->trace(m_timeline);
     visitor->trace(m_compositorPendingAnimations);
     visitor->registerWeakMembers<Document, &Document::clearWeakMembers>(this);
     DocumentSupplementable::trace(visitor);
     TreeScope::trace(visitor);
     ContainerNode::trace(visitor);
     ExecutionContext::trace(visitor);
 }
 
 } // namespace WebCore