DO NOT MERGE libutils/Unicode.cpp: Correct length computation and add checks for utf16->utf8 am: 5fce0542b6 am: d0ad14ca21 am: 3841c92912  -s ours am: 247ac63c69  -s ours am: 6179f1a56e am: 451f4b3d04
am: 3c85e4e5e7  -s ours

Change-Id: I2a4bdacfce15e656f487ad24508df3d4066ca8b7