main: Show a warning when gdm is missing

If we are not running under gdm, some functionaliy (such as
the lock screen) does not work, and we should inform the
user about this.

https://bugzilla.gnome.org/show_bug.cgi?id=701212

diff --git a/js/ui/main.js b/js/ui/main.js
index d8b0b9b6a4a3d8fddd8f60f19e9590b3df5404e1..ab5aff0dcbb2471754d1c3aad0676c15c543b10b 100644 (file)
--- a/js/ui/main.js
+++ b/js/ui/main.js
@@ -268,6 +268,13 @@ function _initializeUI() {
                    _('Running a session as a privileged user should be avoided for security reasons. If possible, you should log in as a normal user.'));
         }
 
+        if (sessionMode.currentMode !== 'gdm' &&
+            sessionMode.currentMode !== 'initial-setup' &&
+            screenShield === null) {
+            notify(_('Screen Lock disabled'),
+                   _('Screen Locking requires the GNOME display manager.'));
+        }
+
         LoginManager.registerSessionWithGDM();
 
         let perfModuleName = GLib.getenv("SHELL_PERF_MODULE");