Merge "Change letterbox background default solid color" into udc-qpr-dev am: a7311a25

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24130224



Change-Id: I766411edbe50ea6ff17c0b323af8b884040f34de
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>