GdkWindowWayland: make sure we attach the surface when repainting
GdkWindowWayland: make sure we attach the surface when repainting

Lazily creating the cairo surface that backs a window when we
first paint to it means that the call to
gdk_wayland_window_attach_image() in
gdk_wayland_window_process_updates_recurse() wasn't working the
first time a window was painted.

https://bugzilla.gnome.org/show_bug.cgi?id=698864

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