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

Source/core/dom/MessageEvent.idl

 /*
  * Copyright (C) 2007 Henry Mason <hmason@mac.com>
  * Copyright (C) 2011 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 13 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
 
 [
     GlobalContext=Window&WorkerGlobalScope,
     ConstructorTemplate=Event
 ] 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

[abarth-chromium, 2013/08/19 19:24:58]

Is that enforced by the constructor?

I would remove this comment.

[do-not-use, 2013/08/19 19:45:57]

The specification is using (Window or MessagePort) type, which our bindings
generator does not support. Instead, I decided to use a common parent type
(EventTarget) and add a comment. I do think that the comment helps understanding
what source is.

     [InitializedByEventConstructor, CustomGetter] 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,
                                    [Default=Undefined] optional any dataArg,
                                    [Default=Undefined] optional DOMString originArg,
                                    [Default=Undefined] optional DOMString lastEventIdArg,
                                    [Default=Undefined] optional Window sourceArg,
                                    [Default=Undefined] optional Array messagePorts);
 
     [Custom] 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 Array transferables);
 };