Reduce repetitive EventTarget subclassing

Source/core/events/EventTarget.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  *           (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ skipping 65 matching lines @@
 
 inline DOMWindow* EventTarget::executingWindow()
 {
     if (ScriptExecutionContext* context = scriptExecutionContext())
         return context->executingWindow();
     return 0;
 }
 
 bool EventTarget::addEventListener(const AtomicString& eventType, PassRefPtr<EventListener> listener, bool useCapture)
 {
-    EventTargetData* d = ensureEventTargetData();
-    return d->eventListenerMap.add(eventType, listener, useCapture);
+    return ensureEventTargetData().eventListenerMap.add(eventType, listener, useCapture);
 }
 
 bool EventTarget::removeEventListener(const AtomicString& eventType, EventListener* listener, bool useCapture)
 {
     EventTargetData* d = eventTargetData();
     if (!d)
         return false;
 
     size_t indexOfRemovedListener;
 
@@ skipping 259 matching lines @@
     // they have one less listener to invoke.
     if (d->firingEventIterators) {
         for (size_t i = 0; i < d->firingEventIterators->size(); ++i) {
             d->firingEventIterators->at(i).iterator = 0;
             d->firingEventIterators->at(i).end = 0;
         }
     }
 }
 
 } // namespace WebCore