[gtk+] gtkwindow: fix a critical warning

[Claudio Saavedra <csaavedra src gnome org>]

commit 343a259e4a4e0034ac5f45d0fd564753fa38a142
Author: Claudio Saavedra <csaavedra igalia com>
Date:   Wed Aug 28 20:10:38 2013 +0300

    gtkwindow: fix a critical warning
    
    Do not map the title box if it's not visible.

 gtk/gtkwindow.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 1fe96a8..e9f547f 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -5471,7 +5471,7 @@ gtk_window_map (GtkWidget *widget)
   if (child != NULL && gtk_widget_get_visible (child))
     gtk_widget_map (child);
 
-  if (priv->title_box != NULL)
+  if (priv->title_box != NULL && gtk_widget_get_visible (priv->title_box))
     gtk_widget_map (priv->title_box);
 
   gdk_window = gtk_widget_get_window (widget);