[automerger] String16: remove integer overflows am: d0648d8dc6 am: 9de539d0dd am: 726007edf0 am: 4ca82d1d14 am: 35629db6fe am: dc2153c913 am: f479f90679 am: e9df4d52f7

Change-Id: Ifab7435d2c707247b64b6debccbdd00224bdc6af