Merge "Add shadow to dream overlay home controls button." into udc-dev am: 3502d6ba

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23146423



Change-Id: Ia39a32e2a90648bad1525917f16948553168898e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>