[gtk+] a11y: unref selected item only if it is not NULL

[Alejandro Piñeiro Iglesias <apinheiro src gnome org>]

commit 2be4474a19d16a1a4862d730f5114169b1ccf5ed
Author: Alejandro Piñeiro <apinheiro igalia com>
Date:   Wed Jul 23 17:56:59 2014 +0200

    a11y: unref selected item only if it is not NULL
    
    https://bugzilla.gnome.org/show_bug.cgi?id=733610

 gtk/a11y/gtknotebookpageaccessible.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)
---
diff --git a/gtk/a11y/gtknotebookpageaccessible.c b/gtk/a11y/gtknotebookpageaccessible.c
index a5a2dad..0f57c73 100644
--- a/gtk/a11y/gtknotebookpageaccessible.c
+++ b/gtk/a11y/gtknotebookpageaccessible.c
@@ -152,9 +152,13 @@ gtk_notebook_page_accessible_ref_state_set (AtkObject *accessible)
   atk_state_set_add_state (state_set, ATK_STATE_SELECTABLE);
 
   selected = atk_selection_ref_selection (ATK_SELECTION (page->priv->notebook), 0);
-  if (selected == accessible)
-    atk_state_set_add_state (state_set, ATK_STATE_SELECTED);
-  g_object_unref (selected);
+  if (selected)
+    {
+      if (selected == accessible)
+        atk_state_set_add_state (state_set, ATK_STATE_SELECTED);
+
+      g_object_unref (selected);
+    }
 
   label = get_label_from_notebook_page (GTK_NOTEBOOK_PAGE_ACCESSIBLE (accessible));
   if (label)