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

Source/core/inspector/InspectorInstrumentation.h

 /*
 * Copyright (C) 2010 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 143 matching lines @@
         Page* page = document->page();
         if (!page && document->templateDocumentHost())
             page = document->templateDocumentHost()->page();
         return instrumentingAgentsForPage(page);
     }
     return 0;
 }
 
 inline InstrumentingAgents* instrumentingAgentsForElement(Element* element)
 {
-    return element ? instrumentingAgentsForDocument(element->document()) : 0;
+    return element ? instrumentingAgentsForDocument(&element->document()) : 0;
 }
 
 bool cssErrorFilter(const CSSParserString& content, int propertyId, int errorType);
 
 } // namespace InspectorInstrumentation
 
 InstrumentingAgents* instrumentationForPage(Page*);
 
 InstrumentingAgents* instrumentationForWorkerGlobalScope(WorkerGlobalScope*);
 
 } // namespace WebCore
 
 // This file will soon be generated
 #include "InspectorInstrumentationInl.h"
 
 #include "InspectorInstrumentationCustomInl.h"
 
 #include "InspectorOverridesInl.h"
 
 #endif // !defined(InspectorInstrumentation_h)