If he's just Googling everything then he sounds like a senior developer to me!

I'm half-joking. Obviously you want people who understand the problem you're asking, and who have a good knowledge of the domain, and who can answer based on their experience and knowledge, but if a few lines from the documentation answer your interview question then it's a bad interview question.

What if the candidate had an exceptional memory and had simply memorized the docs? Would that have been acceptable? Of course not. Your job as an interviewer is to ask questions that looking something up in the docs won't answer. After all, when you're in the job, Googling something is a perfectly acceptable strategy.