Remove MessageEvent.webkitInitMessageEvent()

Source/core/events/MessageEvent.idl

Index: Source/core/events/MessageEvent.idl
diff --git a/Source/core/events/MessageEvent.idl b/Source/core/events/MessageEvent.idl
index bcfcc39373017c873cda6b698153e87971e73efc..b9e155bd6527040f75097f8212adc90b62d7087a 100644
--- a/Source/core/events/MessageEvent.idl
+++ b/Source/core/events/MessageEvent.idl
@@ -44,13 +44,4 @@
                                    [Default=Undefined] optional DOMString lastEventIdArg,
                                    [Default=Undefined] optional Window sourceArg,
                                    [Default=Undefined] optional MessagePort[] messagePorts);
-
-    [Custom, MeasureAs=PrefixedInitMessageEvent] void webkitInitMessageEvent([Default=Undefined] optional DOMString typeArg,
-                                         [Default=Undefined] optional boolean canBubbleArg,
-                                         [Default=Undefined] optional boolean cancelableArg,
-                                         [Default=Undefined] optional any dataArg,
-                                         [Default=Undefined] optional DOMString originArg,
-                                         [Default=Undefined] optional DOMString lastEventIdArg,
-                                         [Default=Undefined] optional Window sourceArg,
-                                         [Default=Undefined] optional MessagePort[] transferables);
 };