-typedef struct _GtkWidget GtkWidget;
-typedef struct _GtkHPaned GtkHPaned;
-GtkHPaned* create_split_views( GtkWidget* topleft, GtkWidget* topright, GtkWidget* botleft, GtkWidget* botright );
+ui::HPaned create_split_views( ui::Widget topleft, ui::Widget topright, ui::Widget botleft, ui::Widget botright );