Use EventHandler type instead of EventListener for event handler attributes

Source/modules/websockets/WebSocket.idl

 /*
  * Copyright (C) 2009 Google Inc.  All rights reserved.
  * Copyright (C) 2010, 2011 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 33 matching lines @@
     // ready state
     const unsigned short CONNECTING = 0;
     const unsigned short OPEN = 1;
     const unsigned short CLOSING = 2;
     const unsigned short CLOSED = 3;
     readonly attribute unsigned short readyState;
 
     readonly attribute unsigned long bufferedAmount;
 
     // networking
-    attribute EventListener onopen;
-    attribute EventListener onmessage;
-    attribute EventListener onerror;
-    attribute EventListener onclose;
+    attribute EventHandler onopen;
+    attribute EventHandler onmessage;
+    attribute EventHandler onerror;
+    attribute EventHandler onclose;
 
     [TreatReturnedNullStringAs=Undefined] readonly attribute DOMString protocol;
     [TreatReturnedNullStringAs=Undefined] readonly attribute DOMString extensions;
 
     attribute DOMString binaryType;
 
     [RaisesException] void send(ArrayBuffer data);
     [RaisesException] void send(ArrayBufferView data);
     [RaisesException] void send(Blob data);
     [RaisesException] void send(DOMString data);
 
     [RaisesException] void close([Clamp] optional unsigned short code, optional DOMString reason);
 };