Inherit EventTarget interface instead of duplicating its code

Source/modules/notifications/Notification.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009, 2011, 2012 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 46 matching lines @@
 class Dictionary;
 class NotificationCenter;
 class NotificationPermissionCallback;
 class ResourceError;
 class ResourceResponse;
 class ScriptExecutionContext;
 class ThreadableLoader;
 
 typedef int ExceptionCode;
 
-class Notification : public RefCounted<Notification>, public ScriptWrappable, public ActiveDOMObject, public EventTarget {
+class Notification : public EventTarget, public RefCounted<Notification>, public ScriptWrappable, public ActiveDOMObject {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     Notification();
 #if ENABLE(LEGACY_NOTIFICATIONS)
     static PassRefPtr<Notification> create(const KURL&, ScriptExecutionContext*, ExceptionCode&, PassRefPtr<NotificationCenter> provider);
     static PassRefPtr<Notification> create(const String& title, const String& body, const String& iconURI, ScriptExecutionContext*, ExceptionCode&, PassRefPtr<NotificationCenter> provider);
 #endif
 #if ENABLE(NOTIFICATIONS)
     static PassRefPtr<Notification> create(ScriptExecutionContext*, const String& title, const Dictionary& options);
 #endif
@@ skipping 125 matching lines @@
 #if ENABLE(NOTIFICATIONS)
     OwnPtr<Timer<Notification> > m_taskTimer;
 #endif
 };
 
 } // namespace WebCore
 
 #endif // ENABLE(NOTIFICATIONS) || ENABLE(LEGACY_NOTIFICATIONS)
 
 #endif // Notifications_h