The source project of this merge request has been removed.
backends/native: Set headless mode when no seat_id
On the graphical remote login use case (see gnome-remote-desktop!139 (merged)), a headless gnome-shell will be started for the GDM greeter and another for the user session.
If no seat_id is set by GDM when gnome-session attempts to start these headless gnome-shells (this is currently true at gdm!180 (merged)) then mutter automatically will detect it and will be started headlessly.
If this MR is accepted, the definitions of headless sessions (gnome-headless-login and gnome-headless) won't be needed, making the graphical remote login approach more straightforward.