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<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
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Part of #11916.
r? @SimonSapin
Source-Repo: https://github.com/servo/servo
Source-Revision: 1fabfee27e16a237d8a6a6b2e4aaad5e67311104
