fix for <rdar://problem/4135705> REGRESSION (412-TOT) crash in TV Tracker...

    fix for <rdar://problem/4135705> REGRESSION (412-TOT) crash in TV Tracker widget - KJS::XMLHttpRequest::removeFromRequestsByDocument()

        Reviewed by Darin.

        Synchronous loads don't get added to our requestsByDocument dictionary, so we should try to remove the request in this case.

        * khtml/ecma/xmlhttprequest.cpp: (KJS::XMLHttpRequest::removeFromRequestsByDocument): added checks to make sure request exists before trying to remove it.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@9243 268f45cc-cd09-0410-ab3c-d52691b4dbfc