U sure? Because dromaesaurus lived during the end cretaceous, birds were already a thing. Aurornis, which can be considered the earliest known bird, lived almost 80 million years before dromaesaurus. Even if you meant the dromaesaurid clade, birds aren’t usually classified in it, and possibly predate it.

Tho it’s true that birds are closer to dromaesaurus than to T-Rex, as birds and romaesaurids are part of the maniraptora clade.