I don't know about Chromium specifically, but in general Google requires 2 humans to have looked at every change (normally one is the author, but not necessarily for bot-authored changes).

Google has not really embraced vibe coded slop. Humans are involved before any code merges and the quality bar remains high.

Did you go and look at their open source repositories and open code review tools instead of fearmongering on HN? The answer can be found.