Add meta_activate_session

This will be used on startup to switch to the newly activated session.

src/core/main.c

@@ -502,6 +502,32 @@ meta_register_with_session (void)
   g_free (opt_client_id);
 }
 
+/**
+ * meta_activate_session:
+ *
+ * Tells mutter to activate the session. When mutter is a
+ * Wayland compositor, this tells logind to switch over to
+ * the new session.
+ */
+gboolean
+meta_activate_session (void)
+{
+  if (meta_is_wayland_compositor ())
+    {
+      MetaWaylandCompositor *compositor = meta_wayland_compositor_get_default ();
+      GError *error = NULL;
+
+      if (!meta_wayland_compositor_activate_session (compositor, &error))
+        {
+          g_warning ("Could not activate session: %s\n", error->message);
+          g_error_free (error);
+          return FALSE;
+        }
+    }
+
+  return TRUE;
+}
+
 /**
  * meta_run: (skip)
  *