Merge \"Revert \\\\\\\\\\\\\\"libutils/Unicode.cpp: Correct length computation...

Merge \"Revert \\\\\\\\\\\\\\"libutils/Unicode.cpp: Correct length computation and add checks for utf16->utf8\\\\\\\\\\\\\\" am: 31100293 am: ddd00519 am: b218b2d3 am: 605de743 am: 37826f56 am: 80473d5d am: c06d338a am: e059f5e3 am: 85d694cd am: 9b169f8b am: fd900142  -s ours am: 01799f43 am: 83df11fe\" into nyc-mr1-dev-plus-aosp
am: d3699b3f

Change-Id: Icccae5dfa1c4776e0e434114c113a983d32aa785