Get rid of [Callback] extended attribute for parameters in IDL files

Source/modules/mediastream/RTCPeerConnection.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
@@ skipping 18 matching lines @@
  */
 
 [
     Conditional=MEDIA_STREAM,
     ActiveDOMObject,
     Constructor(Dictionary rtcIceServers, optional Dictionary mediaConstraints),
     RaisesException,
     CallWith=ScriptExecutionContext,
     EventTarget
 ] interface RTCPeerConnection {
-    [RaisesException] void createOffer([Callback] RTCSessionDescriptionCallback successCallback, [Callback,Default=Undefined] optional RTCErrorCallback failureCallback, optional Dictionary mediaConstraints);
+    [RaisesException] void createOffer(RTCSessionDescriptionCallback successCallback, [Default=Undefined] optional RTCErrorCallback failureCallback, optional Dictionary mediaConstraints);
 
-    [RaisesException] void createAnswer([Callback] RTCSessionDescriptionCallback successCallback, [Callback, Default=Undefined] optional RTCErrorCallback failureCallback, optional Dictionary mediaConstraints);
+    [RaisesException] void createAnswer(RTCSessionDescriptionCallback successCallback, [Default=Undefined] optional RTCErrorCallback failureCallback, optional Dictionary mediaConstraints);
 
-    [RaisesException] void setLocalDescription(RTCSessionDescription description, [Callback, Default=Undefined] optional VoidCallback successCallback, [Callback, Default=Undefined] optional RTCErrorCallback failureCallback);
+    [RaisesException] void setLocalDescription(RTCSessionDescription description, [Default=Undefined] optional VoidCallback successCallback, [Default=Undefined] optional RTCErrorCallback failureCallback);
     [GetterRaisesException] readonly attribute RTCSessionDescription localDescription;
 
-    [RaisesException] void setRemoteDescription(RTCSessionDescription description, [Callback, Default=Undefined] optional VoidCallback successCallback, [Callback, Default=Undefined] optional RTCErrorCallback failureCallback);
+    [RaisesException] void setRemoteDescription(RTCSessionDescription description, [Default=Undefined] optional VoidCallback successCallback, [Default=Undefined] optional RTCErrorCallback failureCallback);
     [GetterRaisesException] readonly attribute RTCSessionDescription remoteDescription;
 
     readonly attribute DOMString signalingState;
 
     [RaisesException] void updateIce(optional Dictionary configuration, optional Dictionary mediaConstraints);
 
     [RaisesException] void addIceCandidate(RTCIceCandidate candidate);
 
     readonly attribute DOMString iceGatheringState;
     readonly attribute DOMString iceConnectionState;
 
     sequence<MediaStream> getLocalStreams();
     sequence<MediaStream> getRemoteStreams();
     MediaStream getStreamById(DOMString streamId);
 
     [StrictTypeChecking, RaisesException] void addStream(MediaStream stream, optional Dictionary mediaConstraints);
     [StrictTypeChecking, RaisesException] void removeStream(MediaStream stream);
 
-    void getStats([Callback] RTCStatsCallback successCallback, [Default=Undefined] optional MediaStreamTrack selector);
+    void getStats(RTCStatsCallback successCallback, [Default=Undefined] optional MediaStreamTrack selector);
 
     [RaisesException] RTCDataChannel createDataChannel([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString label, optional Dictionary options);
 
     [RaisesException] RTCDTMFSender createDTMFSender(MediaStreamTrack track);
 
     [RaisesException] void close();
 
     attribute EventListener onnegotiationneeded;
     attribute EventListener onicecandidate;
     attribute EventListener onsignalingstatechange;
     attribute EventListener onaddstream;
     attribute EventListener onremovestream;
     attribute EventListener oniceconnectionstatechange;
     attribute EventListener ondatachannel;
 
     // 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);
 };