If a child window of the same size is unmapped, we should stop walking
the tree looking for the surface window to use.
Whatever lies beneath is not visible anyway.
This also fixes an issue with the Damage list becoming corrupted when
destroying a window, because the first thing that DeleteWindow() does
is to unmap the window and crush the window tree underneath it.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Fixes: 3a0fc268 - xwayland: Add xwl_window::surface_window
Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1680
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1564>