I don’t have a dog, but here’s what I found online.
I just quickly went to the WDW site for the policy on pets staying onsite. Policy changed Oct. 2017. There are 4 dog friendly WDW hotels, Art of Animation, Port Orleans Riverside, Yacht Club and the Cabins at Ft. Wilderness. There is a limit of 2 dogs per room and a nightly cleaning charge of $50 at each hotel, except the Yacht Club which charges $75. Call 407-W-DISNEY for more info. It looks as though you would have to identify that you need a dog friendly room on your reservation at WDW.
And, there’s a stickie in the Disney Resorts forum about WDW’s policy on dogs at the resorts.
If memory serves, the CAA booklets identify hotels that are pet-friendly.