Merge "Allow settings app to request pin appwidgets from other apps." into udc-qpr-dev am: 732bb20fe1

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24933432

Change-Id: I0515f129d3f16167e6f83b0746bb30f494401faf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>