Have Node::document() return a reference instead of a pointer

Source/core/html/HTMLTableSectionElement.cpp

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2010 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
@@ skipping 46 matching lines @@
 // these functions are rather slow, since we need to get the row at
 // the index... but they aren't used during usual HTML parsing anyway
 PassRefPtr<HTMLElement> HTMLTableSectionElement::insertRow(int index, ExceptionState& es)
 {
     RefPtr<HTMLTableRowElement> row;
     RefPtr<HTMLCollection> children = rows();
     int numRows = children ? (int)children->length() : 0;
     if (index < -1 || index > numRows)
         es.throwDOMException(IndexSizeError); // per the DOM
     else {
-        row = HTMLTableRowElement::create(trTag, document());
+        row = HTMLTableRowElement::create(trTag, &document());
         if (numRows == index || index == -1)
             appendChild(row, es);
         else {
             Node* n;
             if (index < 1)
                 n = firstChild();
             else
                 n = children->item(index);
             insertBefore(row, n, es);
         }
@@ skipping 67 matching lines @@
 {
     setAttribute(valignAttr, value);
 }
 
 PassRefPtr<HTMLCollection> HTMLTableSectionElement::rows()
 {
     return ensureCachedHTMLCollection(TSectionRows);
 }
 
 }