Merge "Allow WindowState to assign layer during transition." into udc-dev am:...

Merge "Allow WindowState to assign layer during transition." into udc-dev am: 28017afd am: 4d6ffc33

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23127077



Change-Id: I4e9f002d0986d35711e57dcace35ae16c44f03ae
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>