Merge cherrypicks of ['ag/20890015'] into tm-qpr2-release.

Change-Id: I3ef16809d395b88f183914f6ff805ebb960d45f2
tree: 3e731d67248ad5e29f07ac96145fd6cd135a49f3
  1. Android.bp
  2. CarMessengerApp.apk
  3. OWNERS
  4. ReadMe.txt
  5. update_prebuilt.sh