Merge "Fill in javadocs for translation feature." into sc-dev am: 1553fc7fad am: 44ef83555f am: c6caf136f5 am: 4e3a00abbc

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15597859

Change-Id: Ic6237aa10cb8aa234a82c9a0c770454ff8f117e5