libviewer.so on Android, delete hello_skia_app

This spins off parts of 5620 to bake while we work through how to do the rest of libviewer.so -> viewer.apk.

Change-Id: I1cbf135cc952eeb7593e80a5a752dcadaa2dbb00
Reviewed-on: https://skia-review.googlesource.com/5656
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
10 files changed