Merge "Explain how to get a tombstone proto." am: 8c8df228 am: 4ab113b8...

Merge "Explain how to get a tombstone proto." am: 8c8df228 am: 4ab113b8 am: a11fd621 am: 9b3927f4 am: 069908a1

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2215564



Change-Id: I848719b0e6fb5b584d8d293ecc02524b3e39e4db
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>