If you're implementing an API, you don't need a license... (or at least you shouldn't). You are implementing something based upon given facts, which can't be copyrighted. Google thought that didn't need a license in the first place.

And that's the crux of this case... is an API copyrightable?

Well, doesn't it seem like the circuit court has answered this question in the affirmative?

Samba and Mono, just to name a few, are pretty big-name open source projects that implement APIs without consent of the creator of those APIs. And even the Linux kernel uses the same system call API as AT&T Unix...

Google used Apache Harmony, I suppose that they complied with its license.