Merge "Fix stalled background thread bug" into udc-dev am: b739e148 am: 9dfb3186

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23765836



Change-Id: I77f94a2eb197a16eebbfd61802a787faf400f102
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>