[gtk+] listboxrowaccessible: Avoid assertion failure

[Matthias Clasen <matthiasc src gnome org>]

commit fb7d7109317d75745b3496efee834bec2c943131
Author: Timm Bäder <mail baedert org>
Date:   Sat Jul 26 13:38:55 2014 +0200

    listboxrowaccessible: Avoid assertion failure
    
    The next call to gtk_list_box_get_selection_mode just expected the
    GtkListBoxRow's parent to be a GtkListBox and failed when the row was
    added to something other than a GtkListBox.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=733782

 gtk/a11y/gtklistboxrowaccessible.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gtk/a11y/gtklistboxrowaccessible.c b/gtk/a11y/gtklistboxrowaccessible.c
index 13831ae..27f9623 100644
--- a/gtk/a11y/gtklistboxrowaccessible.c
+++ b/gtk/a11y/gtklistboxrowaccessible.c
@@ -51,6 +51,7 @@ gtk_list_box_row_accessible_ref_state_set (AtkObject *obj)
     {
       parent = gtk_widget_get_parent (widget);
       if (parent != NULL && 
+          GTK_IS_LIST_BOX (parent) &&
           gtk_list_box_get_selection_mode (GTK_LIST_BOX (parent)) != GTK_SELECTION_NONE)
         atk_state_set_add_state (state_set, ATK_STATE_SELECTABLE);