[lozenge]

I can understand Android (including the Linux kernel) being "too big" and "too separate" to go into Google3, but why Chromium? When it was forked from KHTML/WebKit it was probably not that big compared to the rest of Google's codebase.

[Arainach]

Chromium is open source. As such it needs to be hosted via a publicly accessible stack (Git/Gerrit) so that external contributors can use it.

Size has nothing to do with it.

[eddd-ddde]

This is not a complete answer.

There are many open source projects that are developed in google3.

[randomCloud]

Good old capybara