README

The cc crate is used by various build.rs build scripts to compile C/C++ dependencies of a Rust crate.

In Chromium, these should be compiled as a GN source_set target, and then linked in with the Rust crate explicitly.

Thus no cc crate should ever be imported to third_party. Usage of cc from build.rs files should be commented out, and the dependency should be removed from Cargo.toml files.