Merge "Add String16#contains and strstr16 methods." into nyc-dev am: 8b452b876b
am: 3fe4a71e5f

* commit '3fe4a71e5fb3d4727bc22e5ab6cfc96ffdb6bb87':

Change-Id: I65a71f372aa0656b6665d84d340851f0d02a12ae