am 9b3f3f27: Merge change 1954 into donut

Merge commit '9b3f3f27fe9d50927fe176ebcb2f8b14e226d0b8'

* commit '9b3f3f27fe9d50927fe176ebcb2f8b14e226d0b8':
  Add a bunch of documentation for the Android C library and the JNI interface to the NDK