They do have hair dryers in them. They are the small wall mounted ones. If she prefers something stronger, I would suggest bringing hers. I thinks its fine for short hair, but anything with length would take some time to dry.
Totally agree with ash&abby'smom. Unless packing space was at an absolute premium, I wouldn't even check whether or not a hotel has a hair dryer. It would be rare to find a hair dryer in a hotel room that dries the way I am used to at home. My hair is only short-medium but the hotel dryers just don't have that much power.
I agree with the other posters. I have thick medium length hair and there is no way that little hair dryer would ever work for me. I would advise her to take her own, unless she has really short thin hair.