libutils/Unicode.cpp: Correct length computation and add checks for utf16->utf8 am: 53473c1607 am: 41e6690d0c am: 29ccafe5f0 am: fd7bd2dfef am: 498ffa62c5 am: 5e4ebd02d4 am: d837e74381 am: 6025b216e4
am: a73f7e5e81

Change-Id: Ia2dcdfa5e373ba9bab53faf267650848370d4f93