Hard chrome is an industrial plating specifically for hard-use tool surfaces including chisels, saws, drill bits, grinders, etc. It is meant to be put through hell.
You are not going to hurt it using standard guncleaning solvents, cleaners, wipes or coatings. I have found that my hardchromed guns clean so much easier since nothing wants to stick to that slick surface. I usually just wipe down the surface with my cleaning rags and lightly grease moving parts.
You'll be very happy when you get your pistola back.