combobox: Remove cell_view_frame
combobox: Remove cell_view_frame

Cell views can draw their own frames now.

Adamovskiy/gtk,grubersjoe/adwaita,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,chergert/gtk,alexlarsson/gtk,jigpu/gtk,davidgumberg/gtk,jadahl/gtk,jadahl/gtk,davidgumberg/gtk,chergert/gtk,grubersjoe/adwaita,jadahl/gtk,jigpu/gtk,alexlarsson/gtk,davidgumberg/gtk,jigpu/gtk,grubersjoe/adwaita,jadahl/gtk,jadahl/gtk,jadahl/gtk,jadahl/gtk,chergert/gtk,grubersjoe/adwaita,Adamovskiy/gtk,alexlarsson/gtk,grubersjoe/adwaita,davidgumberg/gtk,Adamovskiy/gtk,chergert/gtk,davidgumberg/gtk,davidgumberg/gtk,Adamovskiy/gtk,Adamovskiy/gtk,jigpu/gtk,chergert/gtk,jadahl/gtk,chergert/gtk,grubersjoe/adwaita,davidgumberg/gtk,jigpu/gtk,grubersjoe/adwaita,alexlarsson/gtk,jigpu/gtk,davidgumberg/gtk,jigpu/gtk,jigpu/gtk,Adamovskiy/gtk,alexlarsson/gtk,Adamovskiy/gtk,chergert/gtk,alexlarsson/gtk,Adamovskiy/gtk,chergert/gtk