[gtk+] Ensure harder a GtkStyleContext has a theming engine anytime

[Carlos Garnacho <carlosg src gnome org>]

commit f482d4dc89b9cb75bf1fab539d1f7b065c494baa
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Jan 17 03:56:47 2011 +0100

    Ensure harder a GtkStyleContext has a theming engine anytime

 gtk/gtkstylecontext.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index 8e01b9c..e36bef4 100644
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -1165,6 +1165,10 @@ style_data_lookup (GtkStyleContext *context)
   gtk_style_properties_get (data->store, 0,
                             "engine", &priv->theming_engine,
                             NULL);
+
+  if (!priv->theming_engine)
+    priv->theming_engine = g_object_ref (gtk_theming_engine_load (NULL));
+
   return data;
 }