Merge "Enable blur letterbox wallpaper behind flags" into udc-qpr-dev am: 9c84b517

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23874759



Change-Id: I8d26028646ec316ad449df8546c81872ff56e48c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>