[gtk+] GtkListBoxRow: add g_return_if_fail to grab_focus, don't crash

[Matthias Clasen <matthiasc src gnome org>]

commit 3ce3593ebf334f0bee2497732ebce8958e9950e0
Author: Rafal Luzynski <digitalfreak lingonborough com>
Date:   Thu Feb 26 02:15:18 2015 +0100

    GtkListBoxRow: add g_return_if_fail to grab_focus, don't crash
    
    Although gtk_list_box_row_grab_focus() is not a public function
    it can be easily called by gtk_widget_grab_focus() with a row argument
    which has been removed from the list box and has box == NULL.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=744879

 gtk/gtklistbox.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtklistbox.c b/gtk/gtklistbox.c
index 06ccaee..b270910 100644
--- a/gtk/gtklistbox.c
+++ b/gtk/gtklistbox.c
@@ -3487,6 +3487,8 @@ gtk_list_box_row_grab_focus (GtkWidget *widget)
   GtkListBoxRow *row = GTK_LIST_BOX_ROW (widget);
   GtkListBox *box = gtk_list_box_row_get_box (row);
 
+  g_return_if_fail (box != NULL);
+
   if (BOX_PRIV (box)->cursor_row != row)
     gtk_list_box_update_cursor (box, row, FALSE);