Android: Explain android_deps visibility

Also add missed transitive testonly dep from: https://crrev.com/c/1493204
Not security critical, original CL already approved, no need for
additional licensing or security review for this transitive dep.

Bug: 946331
Change-Id: Ide882486466ae43487484c83789926c99043033d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1541588
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Sam Maier <smaier@chromium.org>
Commit-Queue: Peter Wen <wnwen@chromium.org>
Auto-Submit: Peter Wen <wnwen@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#644867}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: c620e004b2537ddf1f1e69a8c588ad23013ed565
2 files changed