Merge "Change unfold background color based on split screen state" into udc-dev am: 550f35fc

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23083218



Change-Id: I3374a35e092d91d6272d1935ddf4a185bfd55c1c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>