Chromium codebase is a massive codebase. It works, its efficient and fast, its sophisticated and complex, its well tested, had all sort of bugs that was taken out of them. Its really well written C++ code with modern ownership semantics. So a lot of mistakes that are used as boogeyman to convince people to use Rust are barely problems you really face.
And no matter what wonders Rust promisses, a lot of bugs would get back there in case of rewriting things.
Rust can make a very good point when the thing to be rewritten is in C (if is not a billion dollar codebase like Linux). But with big codebases, well written and modern C++ it doesnt make sense at all.
I get it why someone would start a new project in Rust though.. but the things dont add up when we talk about big codebases already coded with good C++ practices.
