Merge "Use status bar appearance to determine header element brightness." into udc-qpr-dev am: f502b11399 am: e32c6e284d

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23517670

Change-Id: I0d64a2c28d09fc13fff4460d84009eb2f7554d03
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>