Merge "Only draw legacy nav bar background when it is visible" into udc-qpr-dev am: e4ef060e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24735364



Change-Id: I5028cb294379e9f478e7aeed95f9263a2fc0382a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>