Google's open source projects are open in name only.
The link at the top of the page is pointing to the GitHub repo, where you can see literally over a million contributions from thousands of people working at hundreds of companies: https://github.com/chromium/chromium/commits/main
I've worked on both Chrome and Android (Chromium and AOSP) professionally, and never worked at Google.
What I should've written is that: yes, they are open source, but there's no way to influence the direction they are going. These projects are 100% Google-run, and very few (if any) decisions are public.
For most projects there's also a significant proprietary part in the actual final product