gdkwindow: Use an InputOnly window for focus_window
gdkwindow: Use an InputOnly window for focus_window

For XWayland, this is somewhat important to prevent a dummy XWayland surface
being made for all clients that connect...

https://bugzilla.gnome.org/show_bug.cgi?id=723390

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