mozilla crashed when open file where there is an chinese name file under the directory
check return value of GetUnicodeLeafName() also call Reset() for encoder and decoder to reset the state
r=shanjian,sr=darin,a=asa
git-svn-id: svn://10.0.0.236/trunk@118518 18797224-902f-48f8-a5cc-f745e15eee43
163e69b679