Merge "DO NOT MERGE Disallow Wallpaper service to launch activity from background." into tm-dev am: caf5747b97

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23912846

Change-Id: If0fcb99bd5ba47a3528a6481b2c66ce89fb2a41c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>