Merge "Animate status bar alpha during dream<->lockscreen transitions." into udc-qpr-dev am: 2200a33686 am: f0966e6594

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24343672

Change-Id: I6fb2ea647cae8d025acba9a708475e6f2426e6ae
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>