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

Change-Id: Ia8ee4d393bc8cf9cde7ada6af9f79eeee3100f80