* app/widgets/gimpdatafactoryview.[ch]
(gimp_data_factory_view_have)
(gimp_data_factory_view_get_children_type)
(gimp_data_factory_view_has_data_new_func): New helper functions
to lesser level of indirection in client code.

* app/actions/data-commands.c: Use them.

svn path=/trunk/; revision=27814