stylo: Bug 1346052 - Add Servo_AnimationValue_Compute.
This is an interdependent patch of Bug 1346052. We need this FFI to compute the AnimationValue from a property id and a string, so nsDOMWindowUtils::ComputeAnimationDistance() can use this FFI to get the AnimationValue.
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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 [Bug 1346052](https://bugzilla.mozilla.org/show_bug.cgi?id=1346052).
- [X] These changes do not require tests because we have some tests for this in Gecko.
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This is a verbatim copy of the source at [1]. It won't compile on stable rust,
but I'm including it here to make the changes clear.
[1] https://doc.rust-lang.org/src/alloc/arc.rs.html
MozReview-Commit-ID: XEbOK4fXQX
Make stylo support mozmm unit
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This issue is reported at https://bugzilla.mozilla.org/show_bug.cgi?id=1356104. Mozmm is defined at https://developer.mozilla.org/zh-TW/docs/Web/CSS/length.
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- [X] These changes fix [Bug 1356104](https://bugzilla.mozilla.org/show_bug.cgi?id=1356104)
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Stop using unstable slice_patterns feature
cc #5286
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- [x] `./mach test-tidy` does not report any errors
- [ ] There are tests for these changes OR
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Preserve units in computed Angle
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It was converting all angles to radians before. But other browsers preserves the angle units. Fixed that behavior.
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- [X] These changes fix#16594 and [Bug 1360659](https://bugzilla.mozilla.org/show_bug.cgi?id=1360659)
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Servo changes for bug 1347409
bug 1347409 is introducing a fallback type for SVG paint servers so that we can distinguish between url(something) and url(something) none and serialise those cases correctly. When we get a url(something) color we need to set the mFallbackType to eStyleSVGFallbackType_Color.
This change has already been reviewed in https://bugzilla.mozilla.org/show_bug.cgi?id=1347409
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My measurements are inconclusive as to whether this really moves the
needle, but it seems like the right way to do it in any case.
MozReview-Commit-ID: 7OuCc2aQ7jH
