Merge "Conform the logic to decide wallpaper darkness" into udc-dev am: 223a0a22

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23617998



Change-Id: I937ca08059ee2e6f946c6d026b7daf5fa4263152
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>