Inherit EventTarget interface instead of duplicating its code

Source/modules/webaudio/AudioNode.idl

 /*
  * 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 23 matching lines @@
 
     [SetterRaisesException] attribute DOMString channelCountMode;
 
     [SetterRaisesException] attribute DOMString channelInterpretation;
 
     [RaisesException] void connect(AudioNode? destination, [Default=Undefined] optional unsigned long output, [Default=Undefined] optional unsigned long input);
 
     [RaisesException] void connect(AudioParam? destination, [Default=Undefined] optional unsigned long output);
 
     [RaisesException] void disconnect([Default=Undefined] optional unsigned long output);
-
-
-    // EventTarget interface
-    void addEventListener(DOMString type,
-                          EventListener listener,
-                          optional boolean useCapture);
-    void removeEventListener(DOMString type,
-                             EventListener listener,
-                             optional boolean useCapture);
-    [RaisesException] boolean dispatchEvent(Event event);
 };