Be careful with dogs and chocolate. It's not an urban legend that dogs can be severely harmed by it.
...although I've had two chocolate-loving Golden Retrievers in my life, both of which found ways to get their paws on it when we weren't looking, and both of which never had any problems afterward.
I think the size of dog and the type/amount of chocolate makes a difference too. (Like baking chocolate is apparently far more toxic to them than, say, milk chocolate which is what you eat in most candy bars.) Still be careful though!