There’s also a popover div ad in gmail: https://twitter.com/ridiculous_fish/status/10810743891336806...
Disclaimer: I am the creator of the video
I too remember seeing this ad every time on Google's search page, but it's hard to search for articles mentioning it now, because any search on keywords "google chrome ads" return completely unrelated results.
There are these old questions:
* https://support.google.com/chrome/forum/AAAAP1KN0B0FrX8mjNQu...
* https://support.google.com/websearch/forum/AAAAgtjJeM41xpRdM...
* https://support.google.com/chrome/forum/AAAAP1KN0B08liXq3dy9...
* https://www.quora.com/Why-am-I-being-shown-ads-for-Google-Ch...
Also this news piece: https://www.techspot.com/news/79940-how-youtube-employees-ki... While the article is about Google advertising three different browser in that particular banner, you can see on the screenshot there is another ad, that is just for Google Chrome. That's the ad that was shown all the time on Google Search and Youtube.
Speaking as a dev, the dev tools had a ton to do with it.