Code review comment for lp:~robertcarr/mir/client-focus-notifications

Looks good overall. One question:

486 + if (current_focus)
487 + current_focus->configure(mir_surface_attrib_focus, mir_surface_unfocused);
488 + surface->configure(mir_surface_attrib_focus, mir_surface_focused);.

Is there a way for the currently focused surface to get the focus again, and receive a confusing [unfocused,focused] sequence of events? We don't seem to guard against this, at least not at this level.