Inherit EventTarget interface instead of duplicating its code

Source/modules/indexeddb/IDBTransaction.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 @@
 namespace WebCore {
 
 class DOMError;
 class IDBCursor;
 class IDBDatabase;
 class IDBDatabaseBackendInterface;
 class IDBObjectStore;
 class IDBOpenDBRequest;
 struct IDBObjectStoreMetadata;
 
-class IDBTransaction : public ScriptWrappable, public RefCounted<IDBTransaction>, public EventTarget, public ActiveDOMObject {
+class IDBTransaction : public EventTarget, public ScriptWrappable, public RefCounted<IDBTransaction>, public ActiveDOMObject {
 public:
     static PassRefPtr<IDBTransaction> create(ScriptExecutionContext*, int64_t, const Vector<String>& objectStoreNames, IndexedDB::TransactionMode, IDBDatabase*);
     static PassRefPtr<IDBTransaction> create(ScriptExecutionContext*, int64_t, IDBDatabase*, IDBOpenDBRequest*, const IDBDatabaseMetadata& previousMetadata);
     virtual ~IDBTransaction();
 
     static const AtomicString& modeReadOnly();
     static const AtomicString& modeReadWrite();
     static const AtomicString& modeVersionChange();
     static const AtomicString& modeReadOnlyLegacy();
     static const AtomicString& modeReadWriteLegacy();
@@ skipping 100 matching lines @@
     IDBDatabaseMetadata m_previousMetadata;
 
     HashSet<IDBCursor*> m_openCursors;
 
     EventTargetData m_eventTargetData;
 };
 
 } // namespace WebCore
 
 #endif // IDBTransaction_h