Use EventHandler type instead of EventListener for event handler attributes

Source/modules/mediastream/RTCDataChannel.idl

 /*
  * Copyright (C) 2012 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 31 matching lines @@
 
     [SetterRaisesException] attribute DOMString binaryType;
 
     [RaisesException] void send(ArrayBuffer data);
     [RaisesException] void send(ArrayBufferView data);
     [RaisesException] void send(Blob data);
     [RaisesException] void send(DOMString data);
 
     void close();
 
-    attribute EventListener onopen;
-    attribute EventListener onerror;
-    attribute EventListener onclose;
-    attribute EventListener onmessage;
+    attribute EventHandler onopen;
+    attribute EventHandler onerror;
+    attribute EventHandler onclose;
+    attribute EventHandler onmessage;
 };