This is blatant misinformation. Firefox (and all of its derivatives) also does this.
That can only happen if the extension itself leaks it to the web page and if that happens, scanning isn't necessary since it already leaked what it is to the webpage. It also doesn't tell you what extension it is, unless again, the extension leaks it to the webpage.
The attack on Chrome is far more useful for attackers as web pages can scan using the chrome store's extension ID instead.
Point being: Google will 100% give your info to the police, regardless of whether the police have the legal right to it or not, and regardless of whether you actually committed a crime or not.
Bonus points: the federal court that ruled on the case said that it likely violated the fourth amendment, but they allowed the police to admit the evidence anyway because of the "good faith" clause, which is a new one for me. Time to add it to the list of horribly abusable exceptions (qualified immunity, civil asset forfeiture, and eminent domain coming to mind).
The bad guy here is google. And the people that champion data collection by private companies because of free market == good.