Imagine what an app could do if they had access to your entire message history! (Why would anyone give apps access to their messages? So that they can send / receive special emoji, for example.)
Either way, discrete and easy-to-digest information like 'likes' are exactly what they wouldn't have access to from Google, and honestly it seems like automated sentiment analyses are still very error-prone; large corpuses of text don't seem ideal for this sort of targeting.
It's all privacy leakage but it's not at all the same data. Facebook's graph is still noisy but it's better or at least different data than other companies have.
I don't think Google does that...