am 50bbc0ca: am 465c7c26: (-s ours) DO NOT MERGE cherrypick from jb-mr2-ub-dev docs: NDK r9 Release Notes (w/download size fix)

* commit '50bbc0ca84caf504dcc1b5e0fb58919dce5b917b':
  DO NOT MERGE cherrypick from jb-mr2-ub-dev docs: NDK r9 Release Notes (w/download size fix)