Merge "Toggle dim according to progress of recents animation" into udc-dev am: f51e5001 am: 20622b97 am: 818fb77f am: 361ea5d6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23693824



Change-Id: I773389e84075ba22cce8e2687e99670838daf84e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>