[gtk+/xi2: 1200/1239] gdk_window_get_device_events: Fix potential critical warning.

[Carlos Garnacho <carlosg src gnome org>]

commit 2a2efc2b5d24d397d59fb0aedd25012ec657ee98
Author: Carlos Garnacho <carlos gnome org>
Date:   Sun Sep 20 16:34:31 2009 +0200

    gdk_window_get_device_events: Fix potential critical warning.

 gdk/gdkwindow.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index c090fb3..fecd813 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -6747,6 +6747,10 @@ gdk_window_get_device_events (GdkWindow *window,
     return 0;
 
   private = (GdkWindowObject *) window;
+
+  if (!private->device_events)
+    return 0;
+
   mask = GPOINTER_TO_INT (g_hash_table_lookup (private->device_events, device));
 
   /* FIXME: device could be controlled by private->event_mask */