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

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



Change-Id: I084965f813bc0f599f491a9e48d107e7633eabbc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>