9a83662a18
With fallback mode dropped, we can no longer rely on gnome-screensaver to be installed, so we'll have cases where we are unable to lock the screen. The user menu should not show the "Lock" item in this case, but as UnlockDialog includes UserMenu, we cannot use the existing check without creating a circular dependency; move the function to a more generic place to fix. https://bugzilla.gnome.org/show_bug.cgi?id=693403