Merge "Synchronize broadcasts so that beginBroadcast does not get called...

Merge "Synchronize broadcasts so that beginBroadcast does not get called twice" into udc-dev am: 3b6d92d5 am: b6a5a3c6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22390180



Change-Id: I7f3ec4cd71a06e8fc7dcf4474ddf480447f64783
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>