Those may be OK, but they make me nervous. They don't look like they have a real tight seal (could be wrong). The Home Depot guys will tell you can use any shower trim that is enclosed, has a foam gasket and is rated for wet locations. I think they're nuts and those trims should only be used above open showers or similar locations and couldn't handle a steamroom where they are pounded by steam constantly.
I found these in my travels:
Steam&Sauna Lights (3/4 down the page)
But then I wound up just using a solid glass wall/door and moving my recessed can light just outside the shower. Still get plenty of light that way but none of the steam-leaking headaches. If you had a larger shower (mine is only 4' wide and 3' deep and were worried about the light coming far enough in you could even put in one of those wall washers trims to focus the light inside the shower.