bug#46827: Broken initial size of GTK3 frame

[martin rudalics]

> I still don't see the problem, because that last check you show above
> will catch that, right?

You mean that if windows_or_buffers_changed, we handle that in the last
check and all the former check has to do is to assure that the selected
window is right?  Then why do we call do_pending_window_change at all in
the "second" case.  Because we might go to end_of_redisplay right from
there?  But then the third check won't catch it.  I'm clearly confused.

> SET_FRAME_GARBAGED also causes windows_or_buffers_changed to be set.

Via 'redisplay_other_windows', I see.

martin