Hide Udfps icon when shade is expanded
1) Adds interface for ScrimController to notify listeners of new
alpha
2) For SysUI modules such as UdfpsView that have views in layers
ABOVE the notification shade (such as during lockscreen auth),
yet need to pretend to be behind the shade (such as during
enrollment), this allows UdfpsView to set its alpha and color
to the right level
Bug: 177931181
Test: atest com.android.systemui.biometrics
Change-Id: I9b7bd5d72acee8ccbba9aef5b1c935bbf1da815f
8 files changed