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

Change-Id: Ie620548a78c92d2160db4395f00c6ec9f281e937