Accessibility focus not cleared on temporary detach.

1. There was a path for removing a view without clearing its accessibility focus.
   Then when we try to draw the focused rectangle we get an exception since the
   accessibility focused view is not attached to the view tree when computing
   the location of the rectangel to draw.

bug:7297191

Change-Id: I81e3c35e830e27cf95e73accb665629d0c456afb