filterlistmodel: Remove pre-filter remnants

We are not using the filter func typdef anymore.

gtk/gtkfilterlistmodel.h

@@ -27,7 +27,6 @@
 
 #include <gio/gio.h>
 #include <gtk/gtkfilter.h>
-#include <gtk/gtkwidget.h>
 
 
 G_BEGIN_DECLS
@@ -37,19 +36,6 @@ G_BEGIN_DECLS
 GDK_AVAILABLE_IN_ALL
 G_DECLARE_FINAL_TYPE (GtkFilterListModel, gtk_filter_list_model, GTK, FILTER_LIST_MODEL, GObject)
 
-/**
- * GtkFilterListModelFilterFunc:
- * @item: (type GObject): The item that may be filtered
- * @user_data: user data
- *
- * User function that is called to determine if the @item of the original model should be visible.
- * If it should be visible, this function must return %TRUE. If the model should filter out the
- * @item, %FALSE must be returned.
- *
- * Returns: %TRUE to keep the item around
- */
-typedef gboolean (* GtkFilterListModelFilterFunc) (gpointer item, gpointer user_data);
-
 GDK_AVAILABLE_IN_ALL
 GtkFilterListModel *    gtk_filter_list_model_new               (GListModel             *model,
                                                                  GtkFilter              *filter);

testsuite/gtk/filterlistmodel.c

@@ -150,9 +150,9 @@ free_changes (gpointer data)
 }
 
 static GtkFilterListModel *
-new_model (guint                        size,
-           GtkFilterListModelFilterFunc filter_func,
-           gpointer                     data)
+new_model (guint               size,
+           GtkCustomFilterFunc filter_func,
+           gpointer            data)
 {
   GtkFilterListModel *result;
   GtkFilter *filter;