Inherit EventTarget interface instead of duplicating its code

Source/core/workers/WorkerGlobalScope.h

 /*
  * Copyright (C) 2008, 2009 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 35 matching lines @@
 namespace WebCore {
 
     class Blob;
     class DOMURL;
     class ScheduledAction;
     class WorkerInspectorController;
     class WorkerLocation;
     class WorkerNavigator;
     class WorkerThread;
 
-    class WorkerGlobalScope : public RefCounted<WorkerGlobalScope>, public ScriptWrappable, public ScriptExecutionContext, public EventTarget {
+    class WorkerGlobalScope : public EventTarget, public RefCounted<WorkerGlobalScope>, public ScriptWrappable, public ScriptExecutionContext {
     public:
         virtual ~WorkerGlobalScope();
 
         virtual bool isWorkerGlobalScope() const OVERRIDE { return true; }
 
         virtual ScriptExecutionContext* scriptExecutionContext() const OVERRIDE;
 
         virtual bool isSharedWorkerGlobalScope() const { return false; }
         virtual bool isDedicatedWorkerGlobalScope() const { return false; }
 
@@ skipping 115 matching lines @@
 
 inline WorkerGlobalScope* toWorkerGlobalScope(ScriptExecutionContext* context)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!context || context->isWorkerGlobalScope());
     return static_cast<WorkerGlobalScope*>(context);
 }
 
 } // namespace WebCore
 
 #endif // WorkerGlobalScope_h