Merge "Prevent crash when unregsiter the broadcast" into tm-dev am: d7e447b4 am: 36f1a97c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17352123



Change-Id: Ib5ae9578b11f26376280c8936c3b9f485b7e5af5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>