The IP address & user-agent combination alone is enough to track a home user (whose IP doesn't change that often) with a high degree of accuracy, and even more so if you happen to be logged into a Google account in another tab/browser which will allow them to attribute any new IPs to you.
I was saying that being logged-in in one tab would let Google know of any new IP that you would be using, which would in turn allow them to attribute non-logged-in traffic from other tabs because they now know your new IP.
[citation needed]
The IP address & user-agent combination alone is enough to track a home user (whose IP doesn't change that often) with a high degree of accuracy, and even more so if you happen to be logged into a Google account in another tab/browser which will allow them to attribute any new IPs to you.