Merge "Remove light theme support for split screen surface." into udc-dev am: 9779b22c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22955244



Change-Id: If612a2e3e78a287b2b69981334cbed679d90235b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>