Introduce "per task source" cancellation
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- [ ] These changes fix#21119 (github issue number if applicable).
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Don't forward GL parameter gets for constant limits.
This avoids IPC traffic for unchanging constants that are determined when the GL context is created. These changes require https://github.com/emilio/rust-offscreen-rendering-context/pull/123.
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- [x] `./mach build -d` does not report any errors
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- [x] These changes fix#20876.
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Automatically provide a resource reader for tests
Fix#20710
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Use higher level handles from JS bindings
…reak servo
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- [x] These changes fix https://github.com/servo/rust-mozjs/issues/153
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- [x] These changes do not require tests because this is just migration to a lifetimed API
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