Merge "Toggle dim according to progress of recents animation" into udc-dev am: f51e5001

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



Change-Id: I538d5d6eaf2ad12098f6683004c8a1f6defb8c02
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>