This marshaling is slow, because Gecko stores attributes as UTF-16 and does not atomize them in all cases, and it turns out that the need for them in Servo is pretty minimal. With some refactoring across servo and rust-selectors we can fix this.
Source-Repo: https://github.com/servo/servo
Source-Revision: abdf2f28a0bd25a76a31b4fd2410c7a87448ed54
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This allows removing `#![feature(as_unsafe_cell)]` in geckolib and make progress towards #11815.
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix part of #11815.
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- [ ] There are tests for these changes OR
- [x] These changes do not require new tests because they don’t introduce no functional changes.
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Source-Repo: https://github.com/servo/servo
Source-Revision: 3de14d9ca0cf54e6a2ae4eac5ff47e38e724b77b
