Comment 4 for bug 1176234

The current test in http://bazaar.launchpad.net/~ken-vandine/gnome-control-center-signon/autopilot/view/head:/tests/autopilot/gnome_control_center_signon/test_control_center_signon.py doesn't access globalRect. However, I read the code of atk_component_get_extents(), and it indeed just returns without changing its input variables if it's not a valid component. So the attached branch makes sense.

I was going to replicate that in a test, but the current logic makes widgets not have a globalRect property at all until they become visible. I'll try to hide them again and ensure that globalRect has a sensible value.