Roll IDL to 1750

core/events/MessageEvent.idl

Index: core/events/MessageEvent.idl
diff --git a/core/events/MessageEvent.idl b/core/events/MessageEvent.idl
index 33d1c33f462579cc125443c9a8fd11f0db37596f..c482b082cfb950202291ce261805e40cfdb6ac74 100644
--- a/core/events/MessageEvent.idl
+++ b/core/events/MessageEvent.idl
@@ -26,15 +26,15 @@
  */
 
 [
+    EventConstructor,
     GlobalContext=Window&WorkerGlobalScope,
-    ConstructorTemplate=Event
+    RaisesException=Constructor,
 ] interface MessageEvent : Event {
     [InitializedByEventConstructor] readonly attribute DOMString origin;
     [InitializedByEventConstructor] readonly attribute DOMString lastEventId;
-    [InitializedByEventConstructor] readonly attribute EventTarget source; // May be a Window or a MessagePort
-    [InitializedByEventConstructor, CustomGetter] readonly attribute any data;
+    [InitializedByEventConstructor] readonly attribute EventTarget? source; // May be a Window or a MessagePort
+    [InitializedByEventConstructor, Custom=Getter] readonly attribute any data;
     [InitializedByEventConstructor] readonly attribute MessagePort[] ports;
-
     [Custom] void initMessageEvent([Default=Undefined] optional DOMString typeArg,
                                    [Default=Undefined] optional boolean canBubbleArg,
                                    [Default=Undefined] optional boolean cancelableArg,