[gdm] greeter: more robustness fixes against untracked users

[Ray Strode <halfline src gnome org>]

commit 476321d5bd8f007747d23a5856f8f79b6543e0b9
Author: Ray Strode <rstrode redhat com>
Date:   Tue Mar 8 14:57:32 2011 -0500

    greeter: more robustness fixes against untracked users
    
    This is like commit 9ec8f69ce6b225702c4f6bc0475f16d3bc0ef2fa but
    for the update case instead of the add case.

 gui/simple-greeter/gdm-user-chooser-widget.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/gui/simple-greeter/gdm-user-chooser-widget.c b/gui/simple-greeter/gdm-user-chooser-widget.c
index 9551eca..9b4e5de 100644
--- a/gui/simple-greeter/gdm-user-chooser-widget.c
+++ b/gui/simple-greeter/gdm-user-chooser-widget.c
@@ -474,6 +474,18 @@ update_item_for_user (GdmUserChooserWidget *widget,
         }
         escaped_real_name = g_markup_escape_text (real_name, -1);
 
+        /* Ignore updates we aren't interested in */
+        if (!gdm_chooser_widget_lookup_item (GDM_CHOOSER_WIDGET (widget),
+                                             escaped_username,
+                                             NULL,
+                                             NULL,
+                                             NULL,
+                                             NULL,
+                                             NULL,
+                                             NULL)) {
+                return;
+        }
+
         gdm_chooser_widget_update_item (GDM_CHOOSER_WIDGET (widget),
                                         escaped_username,
                                         pixbuf,