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

Merge "Toggle dim according to progress of recents animation" into udc-dev am: f51e5001 am: b94c6db9 am: 5bb30368 am: 35ae6bc5

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



Change-Id: I895b7c10f521d5c763ae531188707e751b8468bb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>