Incorrect temporary detach of accessibility focused view may lead to a crash.

1. If an app naither reattaches nor removes detached view that has
   accessibility focus, an exception in the drawing of accessibility
   focus occurs since we are trying to compute the focused rect by
   offseting the bounds of the focused view in coords of the root
   but the focused one is not attached.

bug:7297191

Change-Id: Ib69d52e474b8ea365754f5311f5e809bd757dd1a