Merge "Fade notifications with background scrim for shade expansion" into...

Merge "Fade notifications with background scrim for shade expansion" into sc-dev am: e7db82a8 am: 93417535 am: b82c6271

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/14426002

Change-Id: Ibbe0e0d8acc6fe1a7decdbb233407da97942e8d9