GtkFileChooser::add_shortcut_folder_uri
Adds a folder URI to be displayed with the shortcut folders in a file chooser. Note that shortcut folders do not get saved, as they are provided by the application. For example, you can use this to add a "file:///usr/share/mydrawprogram/Clipart" folder to the volume list.
See also: remove_shortcut_folder_uri()