patch: cancel background download as soon as user quits r=darin git-svn-id: svn://10.0.0.236/trunk@215474 18797224-902f-48f8-a5cc-f745e15eee43
patch: cancel background download as soon as user quits r=darin git-svn-id: svn://10.0.0.236/trunk@215474 18797224-902f-48f8-a5cc-f745e15eee43