GtkScrolledWindow: Use style classes for shadow
GtkScrolledWindow: Use style classes for shadow

Translate shadow != None into the FRAME style class.
This doesn't change the style classes used for drawing,
it only sets the style class permanently instead of
saving and restoring in draw().
https://bugzilla.gnome.org/show_bug.cgi?id=732256

jadahl/gtk,davidgumberg/gtk,Adamovskiy/gtk,jessevdk/gtk,davidgumberg/gtk,Adamovskiy/gtk,jadahl/gtk,Adamovskiy/gtk,jessevdk/gtk,alexlarsson/gtk,jigpu/gtk,davidgumberg/gtk,Adamovskiy/gtk,jigpu/gtk,ahodesuka/gtk,davidgumberg/gtk,Adamovskiy/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,jigpu/gtk,ahodesuka/gtk,Lyude/gtk-,Adamovskiy/gtk,jadahl/gtk,jigpu/gtk,Lyude/gtk-,davidgumberg/gtk,jadahl/gtk,jigpu/gtk,alexlarsson/gtk,chergert/gtk,Lyude/gtk-,ahodesuka/gtk,chergert/gtk,davidgumberg/gtk,jadahl/gtk,grubersjoe/adwaita,jessevdk/gtk,grubersjoe/adwaita,alexlarsson/gtk,jigpu/gtk,grubersjoe/adwaita,jessevdk/gtk,jessevdk/gtk,chergert/gtk,chergert/gtk,grubersjoe/adwaita,ahodesuka/gtk,ahodesuka/gtk,Lyude/gtk-,Lyude/gtk-,grubersjoe/adwaita,jessevdk/gtk,grubersjoe/adwaita,alexlarsson/gtk,chergert/gtk,Adamovskiy/gtk,jessevdk/gtk,Lyude/gtk-,chergert/gtk,jadahl/gtk,alexlarsson/gtk,Adamovskiy/gtk,jigpu/gtk,jadahl/gtk,ahodesuka/gtk,jadahl/gtk,jigpu/gtk,chergert/gtk,davidgumberg/gtk,chergert/gtk,Lyude/gtk-,Lyude/gtk-,ahodesuka/gtk,davidgumberg/gtk,ahodesuka/gtk,alexlarsson/gtk,grubersjoe/adwaita