Inherit EventTarget interface instead of duplicating its code

Source/modules/indexeddb/IDBRequest.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:
  *
  * 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
@@ skipping 30 matching lines @@
 #include "modules/indexeddb/IDBAny.h"
 #include "modules/indexeddb/IDBCallbacks.h"
 #include "modules/indexeddb/IDBCursor.h"
 
 namespace WebCore {
 
 class IDBTransaction;
 
 typedef int ExceptionCode;
 
-class IDBRequest : public ScriptWrappable, public IDBCallbacks, public EventTarget, public ActiveDOMObject {
+class IDBRequest : public EventTarget, public ScriptWrappable, public IDBCallbacks, public ActiveDOMObject {
 public:
     static PassRefPtr<IDBRequest> create(ScriptExecutionContext*, PassRefPtr<IDBAny> source, IDBTransaction*);
     static PassRefPtr<IDBRequest> create(ScriptExecutionContext*, PassRefPtr<IDBAny> source, IDBDatabaseBackendInterface::TaskType, IDBTransaction*);
     virtual ~IDBRequest();
 
     PassRefPtr<IDBAny> result(ExceptionCode&) const;
     PassRefPtr<DOMError> error(ExceptionCode&) const;
     PassRefPtr<IDBAny> source() const;
     PassRefPtr<IDBTransaction> transaction() const;
     void preventPropagation() { m_preventPropagation = true; }
@@ skipping 89 matching lines @@
     bool m_didFireUpgradeNeededEvent;
     bool m_preventPropagation;
 
     EventTargetData m_eventTargetData;
     DOMRequestState m_requestState;
 };
 
 } // namespace WebCore
 
 #endif // IDBRequest_h