Google have numerous robots that do not say Googlebot in the user-agent. They look just like Android cell phones. That is how they spot malicious sites or sites that are trying to game SEO or what-not. They are not within published CIDR blocks for Google and appear to just use wireless networks.
I'm picturing Google Street View cars driving around with a box of Pixels in the back, connecting to open WiFi and trying sites and that's why Google can now narrow down your location from what SSIDs are available.
