C++ has made it very painless to upgrade from C, by being (mostly) a superset. It's so painless that many codebases haven't really upgraded and it's common to see C-isms sprinkled around larger code bases. Some classes written decades ago can survive the years written in horrible outdated style. For some that might be a feature, but for the quality (or safety) of the code it isn't.

Yes, when there is too much unsafe in a Rust codebase then the unsafe label inflates and the safety guarantees aren't as good. But the conclusion of that shouldn't involve changing definitions of what's unsafe and what isn't, but using less unsafe overall.

Rust can interface with C++, but it isn't well suited for too intimate interfacing. That's not where its strengths lie.

I think that's a different goal from what chrome is looking for. It sounds like they want to be able to use their utilities and other code written in C++ from within rust, not integrated on a macro level.