DO NOT MERGE - Merge pie-platform-release (PPRL.190505.001) into master.

Bug: 132622481
Change-Id: I85bc0434833ce6571510c42ed57c087d6db64d36
tree: e92a8b419a0ff3796e55e99f212516a9b1696cbb
  1. Android.mk
  2. CleanSpec.mk
  3. README
  4. prebuilt/