Added missing comma in {background,mask}-position
<!-- Please describe your changes on the following line: -->
Fixed#15200 - missing comma in serialized {background,mask}-position with multiple values.
---
<!-- 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#15200 (github issue number if applicable).
<!-- Either: -->
- [X] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- 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/16174)
<!-- Reviewable:end -->
Fix scroll root of absolutely positioned elements
Absolutely positioned elements should be given the scroll root of their
containing block and not necessarily the scroll root of their parent.
This fixes several CSS tests, though others are still failing pending a
similar fix for inherited clipping rectangles.
Fixes#13530.
<!-- Please describe your changes on the following line: -->
---
<!-- 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
- [ ] These changes fix #__ (github issue number if applicable).
<!-- Either: -->
- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- 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/16146)
<!-- Reviewable:end -->
Absolutely positioned elements should be given the scroll root of their
containing block and not necessarily the scroll root of their parent.
This fixes several CSS tests, though others are still failing pending a
similar fix for inherited clipping rectangles.
Fixes#13530.
to_css of counter-increment returns none when there are no properties.
<!-- Please describe your changes on the following line: -->
Changed to_css in style::properties::longhands::counter_increment returns "none" if there are no properties defined.
---
<!-- 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#15977 (github issue number if applicable).
<!-- Either: -->
- [X] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- 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/16136)
<!-- Reviewable:end -->
Correct viewport test references
These references were using an incorrect value for the expected
container width. Now that WebRender is no longer clipping to stacking
context boundaries the rendered width is correct (100% of viewport
width = 240px).
Add gradient border support.
webrender add gradient border support in https://github.com/servo/webrender/pull/953. This pr add support in servo.
---
<!-- 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: -->
- [X] These changes do not require tests because it should be covered by wpt
<!-- 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/15905)
<!-- Reviewable:end -->
Make writing-mode affect computed display
<!-- Please describe your changes on the following line: -->
The first manual test-case in #15754 passes now, but the second test-case still renders "Text" horizontally, which is apparently because of servo's experimental support for writing-mode.
---
<!-- 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#15754 (github issue number if applicable).
<!-- Either: -->
- [X] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- 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/16044)
<!-- Reviewable:end -->
Parsing / serialization for CSS contain
Adds parsing / serialization for CSS contain to the style package.
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#15955
- [x] There are tests for these changes
<!-- 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/15972)
<!-- Reviewable:end -->
Don't create a new XHR until the previous one is complete.
This test often times out when run under rr, because the event loop gets flooded with timer events that initiate XHRs before the previous XHR has completed. Additionally, we're running the event handler up to three times per XHR, which is just silly.
<!-- 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/16087)
<!-- Reviewable:end -->
Implement parsing/serialization and glue for will-change property
Implement parsing/serialization and glue for will-change property
---
<!-- 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#15706 (github issue number if applicable).
<!-- Either: -->
- [x] There are tests for these changes
<!-- 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/15813)
<!-- Reviewable:end -->
implement structured clone callbacks - support Blob cloning
<!-- Please describe your changes on the following line: -->
1. Implement stubs for structured clone callbacks.
2. Support Blob cloning.
Partial implementation of https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm
---
<!-- 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
- [ ] These changes fix#15021 (github issue number if applicable).
<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- 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/15519)
<!-- Reviewable:end -->
If a box has a different writing-mode than its containing block, and has a specified display of inline, change the computed display to inline-block.
Also adds the second manual testcase from #15754 as a WPT to assert that the computed display does in fact change.
Addresses #15401
The desired result is for `CSSWideKeyword`s to return false (they are
parsed) and other Custom declaration values to return true (they are unparsed).
