Add a getter for the directory to file system model

This will allow us to aovid reloading if the directory is
unchanged.

gtk/gtkfilesystemmodel.c

@@ -2182,3 +2182,12 @@ _gtk_file_system_model_add_and_query_files (GtkFileSystemModel *model,
                                model);
     }
 }
+
+GFile *
+_gtk_file_system_model_get_directory (GtkFileSystemModel *model)
+{
+  g_return_if_fail (GTK_IS_FILE_SYSTEM_MODEL (model));
+
+  return model->dir;
+}
+

gtk/gtkfilesystemmodel.h

@@ -50,6 +50,7 @@ GtkFileSystemModel *_gtk_file_system_model_new_for_directory(GFile *
                                                              gpointer            get_data,
                                                              guint               n_columns,
                                                              ...);
+GFile *             _gtk_file_system_model_get_directory    (GtkFileSystemModel *model);
 GCancellable *      _gtk_file_system_model_get_cancellable  (GtkFileSystemModel *model);
 gboolean            _gtk_file_system_model_iter_is_visible  (GtkFileSystemModel *model,
 							     GtkTreeIter        *iter);