Of the two I think you'd get a better choice at the Japan Centre. My knowledge of gluten intolerance is zero, but WFC often has bread, bulgar wheat or pasta as part of their dishes, I think I have heard customers ask to replace A with B in their order, but I can't say for definite.
Is rice OK (told you I know nothing about it)? I was going to suggest finding an Indian restaurant, but Vernon has just pointed out that they may cook their food in ghee, which would be a no-no.
We've just noticed that the soy sauce we have in our cupboard contains wheat, so maybe the Japan Centre isn't such a good idea and if you do go there don't choose Fu (gluten sponge cake).