I wonder if this is one of those strategic deals that would lead to an acquisition. With the push surrounding cloud and Google actively competing hard in this space, it would make a lot of sense.
Problem is that (besides for the brand) Cloudflare really has nothing to offer for Google. Google has spent the last 20 years solving the same problems CF is aiming to solve, they've even got a competing service Google PageSpeed that does exactly what CF does, except better (in my personal experience.).
Google sucks at productizing their infrastructure expertise. The underlying tech at Google is indeed better than CloudFlare, but CloudFlare understands marketing, ease-of-use, product simplicity, all those stuff that are necessary to get people to actually use your offering.
I was amazingly surprised by Google Compute Engine. I've never used such a simple IaaS provider. Especially compared to the direction Azure's new portal is taking, GCE is refreshingly simple. EC2 is alright but still feels a lot more complicated than GCE. The UI is simpler, too.
I don't think they need CloudFlare for that though, they just need marketing people to sell it. I can't see CloudFlare acquisition being worth it for Google just for their marketing expertise.