Rubber-stamped by Ada Chan.

* platform/win/Skipped: Added
fast/dom/Window/window-postmessage-clone.html, which was timing out
due to eventSender.beginDragFiles being unimplemented.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@51547 268f45cc-cd09-0410-ab3c-d52691b4dbfc