arrow: Remove unneeded checks
arrow: Remove unneeded checks

Size vfuncs always get non-null out variables passed, so no need to
check for NULL.

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