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

Change-Id: Ibf26d9f029f77f80623ac97633eb8cddbb77fe29