Convert -webkit-linear-gradient coordinate system for Stylo
<!-- Please describe your changes on the following line: -->
This patch will fix the -webkit-linear-gradient direction issue in Stylo. I decided to NOT change the behavior of Servo, because according to the webcompat spec the webkit prefixed version should just be an alias of non-prefixed version. But we might want to remove support for old syntax like "-webkit-linear-gradient(top, ...)" (without "to"), because they are not in the spec anymore.
The Gecko layout system use different coordinate systems for prefixed and non-prefixed version, so I did a conversion, but for Servo I keep the modern version only.
Since I believe we should not support old syntax in Servo, so I'm not going to put the test in Servo. I'll submit my test cases to the Gecko wpt test instead.
---
<!-- 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
- [x] These changes fix [Bug 1372821](https://bugzilla.mozilla.org/show_bug.cgi?id=1372821)
<!-- Either: -->
- [ ] There are tests for these changes OR
- [x] These changes do not require tests because test will be submitted to the Gecko side
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/17428)
<!-- Reviewable:end -->
stylo: Implement font-language-override descriptor for @font-face rule
Generally we use computed values for `@font-face` rule descriptors but that descriptor is a bit different than the others in gecko side. It accepts strings instead of unsigned integer(which is computed value of this property). So we had to use SpecifiedValue for that in here.
---
<!-- 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
- [X] These changes fix [Bug 1355364](https://bugzilla.mozilla.org/show_bug.cgi?id=1355364)
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/17517)
<!-- Reviewable:end -->
style: Cleanup traversal.rs
Mostly reflowing comments that have become too long or two short with
refactorings, and using consistent indentation.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/17523)
<!-- Reviewable:end -->
This will allow us to fix propagation of text-decoration, and also to implement
inlinization of ruby kids.
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
remove various things now that Rust 1.17 is required
std::ptr::eq and Arc::ptr_eq are now usuable, and we can replace a
panic!() with abort().
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because they are trivial replacements.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/17493)
<!-- Reviewable:end -->
When stylo is not enabled in Gecko, the global state initialization
still creates the style thread pool, even when it's not going to be
used. This wastes address space and a little memory.
See https://bugzilla.mozilla.org/show_bug.cgi?id=1374824#c38 and
following comment.
Add get_zero_value for IntermediateSVGPaint.
<!-- Please describe your changes on the following line: -->
This is a PR for https://bugzilla.mozilla.org/show_bug.cgi?id=1371199
---
<!-- 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
<!-- Either: -->
There are tests for these changes, a test case will be landed in reftests in https://bugzilla.mozilla.org/show_bug.cgi?id=1371199
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/17288)
<!-- Reviewable:end -->
