fontchooser: Move the filter func to the visibility func

... instead of rereading all the fonts every time.

With this change, the liststore now contains every font face known to
GTK, so we can actually walk it for matching fonts.

gtk/gtkfontchooserwidget.c

@@ -752,10 +752,6 @@ populate_list (GtkFontChooserWidget *fontchooser,
           const gchar *face_name;
           gchar *font_desc;
 
-          if (priv->filter_func != NULL &&
-              !priv->filter_func (families[i], faces[j], priv->filter_data))
-            continue;
-
           pango_desc = pango_font_face_describe (faces[j]);
           face_name = pango_font_face_get_face_name (faces[j]);
           font_desc = pango_font_description_to_string (pango_desc);
@@ -831,6 +827,25 @@ visible_func (GtkTreeModel *model,
   gchar *font_name, *font_name_casefold, *term_casefold;
   guint i;
 
+  if (priv->filter_func != NULL)
+    {
+      PangoFontFamily *family;
+      PangoFontFace *face;
+
+      gtk_tree_model_get (model, iter,
+                          FAMILY_COLUMN, &family,
+                          FACE_COLUMN, &face,
+                          -1);
+
+      result = priv->filter_func (family, face, priv->filter_data);
+
+      g_object_unref (family);
+      g_object_unref (face);
+      
+      if (!result)
+        return FALSE;
+    }
+
   /* If there's no filter string we show the item */
   search_text = gtk_entry_get_text (GTK_ENTRY (priv->search_entry));
   if (strlen (search_text) == 0)
@@ -1190,9 +1205,7 @@ gtk_font_chooser_widget_set_filter_func (GtkFontChooser  *chooser,
   priv->filter_data = data;
   priv->filter_data_destroy = destroy;
 
-  populate_list (fontchooser,
+  gtk_tree_model_filter_refilter (GTK_TREE_MODEL_FILTER (priv->filter_model));
-                 GTK_TREE_VIEW (priv->family_face_list),
-                 priv->model);
 }
 
 static void