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

Source/modules/mediastream/RTCPeerConnection.idl

Index: Source/modules/mediastream/RTCPeerConnection.idl
diff --git a/Source/modules/mediastream/RTCPeerConnection.idl b/Source/modules/mediastream/RTCPeerConnection.idl
index 7f251f665c3818ba379581ed8ec4a2fa86d9365e..940e96c3ae282486aee62b689e00f2e455146e7d 100644
--- a/Source/modules/mediastream/RTCPeerConnection.idl
+++ b/Source/modules/mediastream/RTCPeerConnection.idl
@@ -36,14 +36,14 @@
     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;
@@ -62,7 +62,7 @@
     [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);