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

Source/bindings/v8/ScriptEventListener.cpp

 /*
  * Copyright (C) 2009 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 42 matching lines @@
 PassRefPtr<V8LazyEventListener> createAttributeEventListener(Node* node, const QualifiedName& name, const AtomicString& value)
 {
     ASSERT(node);
     if (value.isNull())
         return 0;
 
     // FIXME: Very strange: we initialize zero-based number with '1'.
     TextPosition position(OrdinalNumber::fromZeroBasedInt(1), OrdinalNumber::first());
     String sourceURL;
 
-    if (Frame* frame = node->document()->frame()) {
+    if (Frame* frame = node->document().frame()) {
         ScriptController* scriptController = frame->script();
         if (!scriptController->canExecuteScripts(AboutToExecuteScript))
             return 0;
         position = scriptController->eventHandlerPosition();
-        sourceURL = node->document()->url().string();
+        sourceURL = node->document().url().string();
     }
 
     return V8LazyEventListener::create(name.localName().string(), eventParameterName(node->isSVGElement()), value, sourceURL, position, node);
 }
 
 PassRefPtr<V8LazyEventListener> createAttributeEventListener(Frame* frame, const QualifiedName& name, const AtomicString& value)
 {
     if (!frame)
         return 0;
 
@@ skipping 70 matching lines @@
     v8::ScriptOrigin origin = function->GetScriptOrigin();
     if (origin.ResourceName()->IsString() && !origin.ResourceName().IsEmpty())
         sourceName = toWebCoreString(origin.ResourceName());
     else
         sourceName = "";
     lineNumber = function->GetScriptLineNumber();
     return true;
 }
 
 } // namespace WebCore