We have been implementing constructors of Events. MessageEvent has a constructor in JSC (bug 68883), but does not have it in V8.
Created attachment 111741 [details] Patch
Comment on attachment 111741 [details] Patch Clearing flags on attachment: 111741 Committed r97955: <http://trac.webkit.org/changeset/97955>
All reviewed patches have been landed. Closing bug.