Merge "[pm] shell command to wait for handler(s)" into udc-dev am: 5d67812f am: 721f4af1

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23139396



Change-Id: I9e58edaf92d195ab9448c7038a85a247fe5c032a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>