xwayland: Remove stop xserver timeout

Since commit 226afa24a - "Use Xwayland auto-terminate feature", the
callback function shutdown_xwayland_cb() does not check for the
autoclose-xwayland experimental feature anymore.

As a result, when running nested or outside of systemd,
gnome-shell/mutter would quit after 10 seconds unless some X11 window
was mapped.

But now that we rely on Xwayland's own terminate feature, there really is
no need to use any xserver timeout function anymore.

We do not need to keep track of X11 windows being created or unmapped, as
again, Xwayland does all that for us at the client level.

Remove all this code that we do not need anymore.

fixes: 226afa24a - Use Xwayland auto-terminate feature

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2258>

src/wayland/meta-wayland-private.h

@@ -60,7 +60,6 @@ typedef struct
   guint abstract_fd_watch_id;
   guint unix_fd_watch_id;
 
-  guint xserver_grace_period_id;
   struct wl_display *wayland_display;
   struct wl_client *client;
   struct wl_resource *xserver_resource;
@@ -69,8 +68,6 @@ typedef struct
   GCancellable *xserver_died_cancellable;
   GSubprocess *proc;
 
-  GList *x11_windows;
-
   MetaXWaylandDnd *dnd;
 
   gboolean has_xrandr;

src/wayland/meta-xwayland.c

@@ -446,22 +446,10 @@ meta_xwayland_terminate (MetaXWaylandManager *manager)
 {
   MetaDisplay *display = meta_get_display ();
 
-  g_clear_handle_id (&manager->xserver_grace_period_id, g_source_remove);
   meta_display_shutdown_x11 (display);
   meta_xwayland_stop_xserver (manager);
 }
 
-static gboolean
-shutdown_xwayland_cb (gpointer data)
-{
-  MetaXWaylandManager *manager = data;
-
-  meta_verbose ("Shutting down Xwayland");
-  manager->xserver_grace_period_id = 0;
-  meta_xwayland_terminate (manager);
-  return G_SOURCE_REMOVE;
-}
-
 static int
 x_io_error (Display *display)
 {
@@ -489,11 +477,7 @@ static void
 x_io_error_exit (Display *display,
                  void    *data)
 {
-  MetaXWaylandManager *manager = data;
-
   g_warning ("Xwayland just died, attempting to recover");
-  manager->xserver_grace_period_id =
-    g_idle_add (shutdown_xwayland_cb, manager);
 }
 
 static void
@@ -960,48 +944,6 @@ xdisplay_connection_activity_cb (gint         fd,
   return G_SOURCE_REMOVE;
 }
 
-static void
-meta_xwayland_stop_xserver_timeout (MetaXWaylandManager *manager)
-{
-  if (manager->xserver_grace_period_id)
-    return;
-
-  manager->xserver_grace_period_id =
-    g_timeout_add_seconds (10, shutdown_xwayland_cb, manager);
-}
-
-static void
-window_unmanaged_cb (MetaWindow          *window,
-                     MetaXWaylandManager *manager)
-{
-  manager->x11_windows = g_list_remove (manager->x11_windows, window);
-  g_signal_handlers_disconnect_by_func (window,
-                                        window_unmanaged_cb,
-                                        manager);
-  if (!manager->x11_windows)
-    {
-      meta_verbose ("All X11 windows gone, setting shutdown timeout");
-      meta_xwayland_stop_xserver_timeout (manager);
-    }
-}
-
-static void
-window_created_cb (MetaDisplay         *display,
-                   MetaWindow          *window,
-                   MetaXWaylandManager *manager)
-{
-  /* Ignore all internal windows */
-  if (!window->xwindow ||
-      meta_window_get_pid (window) == getpid ())
-    return;
-
-  manager->x11_windows = g_list_prepend (manager->x11_windows, window);
-  g_signal_connect (window, "unmanaged",
-                    G_CALLBACK (window_unmanaged_cb), manager);
-
-  g_clear_handle_id (&manager->xserver_grace_period_id, g_source_remove);
-}
-
 static void
 meta_xwayland_stop_xserver (MetaXWaylandManager *manager)
 {
@@ -1097,9 +1039,6 @@ on_x11_display_closing (MetaDisplay         *display,
   g_signal_handlers_disconnect_by_func (display,
                                         on_x11_display_closing,
                                         manager);
-  g_signal_handlers_disconnect_by_func (display,
-                                        window_created_cb,
-                                        manager);
 }
 
 static void
@@ -1129,20 +1068,10 @@ static void
 on_x11_display_setup (MetaDisplay         *display,
                       MetaXWaylandManager *manager)
 {
-  MetaContext *context = meta_display_get_context (display);
   MetaX11Display *x11_display = meta_display_get_x11_display (display);
-  MetaX11DisplayPolicy x11_display_policy;
 
   meta_xwayland_init_dnd (x11_display);
   meta_xwayland_init_xrandr (manager, x11_display);
-  meta_xwayland_stop_xserver_timeout (manager);
-
-  x11_display_policy = meta_context_get_x11_display_policy (context);
-  if (x11_display_policy == META_X11_DISPLAY_POLICY_ON_DEMAND)
-    {
-      g_signal_connect (display, "window-created",
-                        G_CALLBACK (window_created_cb), manager);
-    }
 }
 
 void