[gtk+] Add an example for custom css

[Matthias Clasen <matthiasc src gnome org>]

commit b23839c7a5ed92959d2badc112d1d4709c1fb64b
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Jan 13 22:19:58 2011 -0500

    Add an example for custom css

 docs/reference/gtk/migrating-GtkStyleContext.xml |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gtk/migrating-GtkStyleContext.xml b/docs/reference/gtk/migrating-GtkStyleContext.xml
index ef87ab5..42ede40 100644
--- a/docs/reference/gtk/migrating-GtkStyleContext.xml
+++ b/docs/reference/gtk/migrating-GtkStyleContext.xml
@@ -556,7 +556,24 @@
       Typically, the provider will be a #GtkCssProvider, which parse CSS
       information from a file or from a string.
     </para>
-
+    <example>
+      <title>Using a custom GtkStyleProvider</title>
+      <programlisting>
+        GtkStyleContext *context;
+        GtkCssProvider *provider;
+
+        context = gtk_widget_get_style_context (widget);
+        provider = gtk_css_provider_new ();
+        gtk_css_provider_load_from_data (GTK_CSS_PROVIDER (provider),
+                                         ".frame1 {\n"
+                                         "   border-image: url('gradient1.png') 10 10 10 10 stretch;\n"
+                                         "}\n", -1, NULL);
+        gtk_style_context_add_provider (context,
+                                        GTK_STYLE_PROVIDER (provider),
+                                        GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+        g_object_unref (provider);
+      </programlisting>
+    </example>
     <para>
       Notice that you can also get style information from custom resources
       by implementing the #GtkStyleProvider interface yourself. This is