Set MessageEvent.source to the newly created port for shared workers' connect events

Source/core/dom/MessageEvent.idl

Index: Source/core/dom/MessageEvent.idl
diff --git a/Source/core/dom/MessageEvent.idl b/Source/core/dom/MessageEvent.idl
index 3bc8866a7ea1161a7c75dadb015e8e6873ad2cd7..33d1c33f462579cc125443c9a8fd11f0db37596f 100644
--- a/Source/core/dom/MessageEvent.idl
+++ b/Source/core/dom/MessageEvent.idl
@@ -31,7 +31,7 @@
 ] interface MessageEvent : Event {
     [InitializedByEventConstructor] readonly attribute DOMString origin;
     [InitializedByEventConstructor] readonly attribute DOMString lastEventId;
-    [InitializedByEventConstructor] readonly attribute Window source;
+    [InitializedByEventConstructor] readonly attribute EventTarget source; // May be a Window or a MessagePort
     [InitializedByEventConstructor, CustomGetter] readonly attribute any data;
     [InitializedByEventConstructor] readonly attribute MessagePort[] ports;