- [x] `./mach build -d` does not report any errors (kinda, need webrender published and Cargo.toml fixed up)
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).
<!-- Either: -->
- [ ] There are tests for these changes OR
- [x] These changes do not require tests because it is a refactoring in which the difference is mostly a compile-time/strong-typing thing with no change to the logic.
Source-Repo: https://github.com/servo/servo
Source-Revision: 18653f69581693a5bae1ce4e350e78bc16159b08