Merge "Allow status bar to be transparent, and clear LIGHT flags." into rvc-dev am: 25602430fd am: e9e55ae825

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/12166023

Change-Id: Ibfb36faf1ec468ae6d59dcbf9a025f89b6fa89be