GtkBinProps.ViewportSourceval make_params :
cont:(([> `viewport ] as 'a) Gobject.param list -> 'b) ->
'a Gobject.param list ->
?hadjustment:Gtk.adjustment Gtk.obj ->
?vadjustment:Gtk.adjustment Gtk.obj ->
?shadow_type:GtkEnums.shadow_type ->
'b