Drop outstanding cairo surfaces when window is made native
Drop outstanding cairo surfaces when window is made native

Any old cairo_surface referencing the old impl window will be wrong
when we make a window native, so drop it.

This fixes bug #599511

Adamovskiy/gtk,simokivimaki/gtk,alexlarsson/gtk,msteinert/gtk,msteinert/gtk,chergert/gtk,chergert/gtk,ahodesuka/gtk,davidt/gtk,Distrotech/gtk2,alexlarsson/gtk,alexlarsson/gtk,Sidnioulz/SandboxGtk,alexlarsson/gtk,Adamovskiy/gtk,jadahl/gtk,ahodesuka/gtk,Lyude/gtk-,grubersjoe/adwaita,jessevdk/gtk,grubersjoe/adwaita,alexlarsson/gtk,davidgumberg/gtk,davidgumberg/gtk,grubersjoe/adwaita,ahodesuka/gtk,bratsche/gtk-,Sidnioulz/SandboxGtk,Lyude/gtk-,chergert/gtk,msteinert/gtk,jadahl/gtk,ahodesuka/gtk,msteinert/gtk,msteinert/gtk,Lyude/gtk-,Adamovskiy/gtk,ebassi/gtk,jigpu/gtk,ahodesuka/gtk,jessevdk/gtk,grubersjoe/adwaita,Distrotech/gtk2,Distrotech/gtk2,Distrotech/gtk2,jigpu/gtk,simokivimaki/gtk,Adamovskiy/gtk,jadahl/gtk,grubersjoe/adwaita,Adamovskiy/gtk,davidt/gtk,Lyude/gtk-,Adamovskiy/gtk,bratsche/gtk-,jadahl/gtk,simokivimaki/gtk,simokivimaki/gtk,chergert/gtk,alexlarsson/gtk,davidgumberg/gtk,davidgumberg/gtk,jigpu/gtk,alexlarsson/gtk,jessevdk/gtk,davidt/gtk,ebassi/gtk,jadahl/gtk,ebassi/gtk,Sidnioulz/SandboxGtk,Sidnioulz/SandboxGtk,chergert/gtk,Distrotech/gtk2,chergert/gtk,grubersjoe/adwaita,Sidnioulz/SandboxGtk,jadahl/gtk,Lyude/gtk-,davidgumberg/gtk,chergert/gtk,Adamovskiy/gtk,bratsche/gtk-,ebassi/gtk,Adamovskiy/gtk,Lyude/gtk-,chergert/gtk,davidgumberg/gtk,bratsche/gtk-,jessevdk/gtk,jadahl/gtk,simokivimaki/gtk,davidgumberg/gtk,jadahl/gtk,Lyude/gtk-,ahodesuka/gtk,davidt/gtk,msteinert/gtk,davidt/gtk,bratsche/gtk-,jigpu/gtk,jigpu/gtk,ahodesuka/gtk,ebassi/gtk,jessevdk/gtk,jigpu/gtk,alexlarsson/gtk,jessevdk/gtk,Lyude/gtk-,Distrotech/gtk2,Sidnioulz/SandboxGtk,grubersjoe/adwaita,davidt/gtk,ebassi/gtk,bratsche/gtk-,jigpu/gtk,simokivimaki/gtk,jessevdk/gtk,ahodesuka/gtk,davidgumberg/gtk,grubersjoe/adwaita,jigpu/gtk