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

Source/core/editing/AppendNodeCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 14 matching lines @@
 
 #include "config.h"
 #include "core/editing/AppendNodeCommand.h"
 
 #include "bindings/v8/ExceptionState.h"
 #include "core/dom/Document.h"
 
 namespace WebCore {
 
 AppendNodeCommand::AppendNodeCommand(PassRefPtr<ContainerNode> parent, PassRefPtr<Node> node)
-    : SimpleEditCommand(parent->document())
+    : SimpleEditCommand(&parent->document())
     , m_parent(parent)
     , m_node(node)
 {
     ASSERT(m_parent);
     ASSERT(m_node);
     ASSERT(!m_node->parentNode());
 
     ASSERT(m_parent->rendererIsEditable() || !m_parent->attached());
 }
 
@@ skipping 15 matching lines @@
 
 #ifndef NDEBUG
 void AppendNodeCommand::getNodesInCommand(HashSet<Node*>& nodes)
 {
     addNodeAndDescendants(m_parent.get(), nodes);
     addNodeAndDescendants(m_node.get(), nodes);
 }
 #endif
 
 } // namespace WebCore