Dark grey overflow in dark mode

Update overflow visibility after setup
Remove BubbleOverflow#getBtn (same as getIconView)

Bug: 158482996
Test: manual => Turn on dark mode
             => Pointer & overflow button/activity use same grey

Change-Id: I0f9c7d8e6dc1ac77e8601f42527f75b1b4e9ef1d
5 files changed