How big of a windshield chip can be properly repaired?

Looking at a used car and there is a really large chip near the top of the windshield, about 2-3 inches away from the top edge. Including the 1/4-inch-ish cracks/streaks around the chip, it's about a quarter size, or maybe just slightly bigger.

Is this actually properly fixable by the dealership? They say they'll get it back to perfect if I am to buy the car, but I'm worried about it seeming perfect but coming back up later.