Inherit EventTarget interface instead of duplicating its code

Source/bindings/v8/custom/V8AudioContextCustom.cpp

 /*
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 53 matching lines @@
         return;
     }
 
     if (!audioContext.get()) {
         throwError(v8SyntaxError, "Error creating AudioContext", args.GetIsolate());
         return;
     }
     
     // Transform the holder into a wrapper object for the audio context.
     v8::Handle<v8::Object> wrapper = args.Holder();
-    V8DOMWrapper::associateObjectWithWrapper(audioContext.release(), &info, wrapper, args.GetIsolate(), WrapperConfiguration::Dependent);
+    V8DOMWrapper::associateObjectWithWrapper<V8AudioContext>(audioContext.release(), &info, wrapper, args.GetIsolate(), WrapperConfiguration::Dependent);
     args.GetReturnValue().Set(wrapper);
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)