As of Google Chrome version 69, Google are treating being logged in to any Google service as the same thing as being logged in to Google Chrome:
Most Google services have for me this in common with Facebook: these services are too deeply integrated and impossible to use in part or isolation. It’s either the entire system or nothing, based on how the question of consent is approached. You would like to use GMail (logged in obviously) but Google search, Youtube, Chrome etc without a login? No can do. You selected strict settings in Facebook for your profile data? You’re just an API/permission redesign away from having your choices nullified. Part of me feels that this Chrome shared computer issue that Googlers mentioned is real, but it’s also just too convenient to solve this by tieing Chrome closer to Google, you know? Note to Google: any time you find the software engineering decisions you’ve made being compared with those made by Facebook, that’s probably not a good thing for your end users these days.