[gtk+/wip/simple-draw3: 21/23] gdkwindow: Don't error out on NULL backgrounds

[Alexander Larsson <alexl src gnome org>]

commit a6bffcfb5723323a99f938bbd02d42cce027f5f8
Author: Alexander Larsson <alexl redhat com>
Date:   Mon Apr 29 18:14:57 2013 +0200

    gdkwindow: Don't error out on NULL backgrounds

 gtk/gtkwidget.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 28683f6..b86fc84 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -6397,10 +6397,11 @@ _gtk_widget_draw_windows (GdkWindow *window,
 
       /* Only clear bg if double bufferer. This is what we used
         to do before, where begin_paint() did the clearing. */
-      if (widget->priv->double_buffered)
+      pattern = gdk_window_get_background_pattern (window);
+      if (pattern != NULL &&
+         widget->priv->double_buffered)
        {
          cairo_save (cr);
-         pattern = gdk_window_get_background_pattern (window);
          cairo_set_source (cr, pattern);
          cairo_paint (cr);
          cairo_restore (cr);