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

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



Change-Id: If916f618a85b248a11260173fc8b75ef0d9fc07c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>