I wouldn't be surprised if the people that did care about that internally at Google either used something like Firefox or had their private build that can run uBlock or similar ;)
In 2011, when I worked at Google (on ads, not on Chrome), I did use Firefox as my main browser. But back then, there was much less need for an ad blocker. I still remember asking my manager whether it was OK to click an ad (from a VPS provider) while browsing from the corporate desktop.
