Add support for keyword values for min-width and max-width
This is a follow-up to #14432 which got closed and can no longer be re-opened.
This PR aims to add support for keyword-values max-content, min-content, fit-content, and fill-available to the properties that use them, namely min-width, min-height, max-width, and max-height.
It's still untested because I still haven't figured out how to do that. I guess I should write or find some web page that uses these properties.
Refs #13821.
<!-- 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: -->
- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix#13821 (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/14740)
<!-- Reviewable:end -->
Implement gecko glue for clip property
<!-- Please describe your changes on the following line: -->
Implemented gecko glue for clip property.
Clip property looks slightly different in gecko. `auto` top and left values are preserved as auto in [gecko](http://searchfox.org/mozilla-central/rev/39e4b25a076c59d2e7820297d62319f167871449/layout/style/nsRuleNode.cpp#10294,10316) but converted to 0 in [servo](https://dxr.mozilla.org/servo/rev/65624dbfc28442b58145215f524eb13aeb2cadf6/components/style/values/specified/mod.rs#942). Gecko is setting `NS_STYLE_CLIP_TOP_AUTO` and `NS_STYLE_CLIP_LEFT_AUTO` flags with that information. But I tried this property in stylo build and it is working correctly like this. It looks like it doesn't change the outcome of the property.
~Do we really need to set these flags?~
Manishearth and bz said that auto and 0 values are same.
---
<!-- 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 1341728](https://bugzilla.mozilla.org/show_bug.cgi?id=1341728)
<!-- Either: -->
- [X] These changes do not require tests because this is stylo side change.
<!-- 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/15710)
<!-- Reviewable:end -->
Implement an ExtremumLength type which contains all the enumerated
keyword values for min-width, min-height, max-width, and
max-height. Then, implement a MinLength which can be used for min-width
and min-height. So far this just maps to Gecko values.
Refs #13821.
Fix parsing methods of column-{gap,width}
<!-- Please describe your changes on the following line: -->
They weren't accepting {normal, auto} keywords. Fixed parsing methods of these properties.
---
<!-- 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#15088 (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/15662)
<!-- Reviewable:end -->
Use bitflags for multikeyword properties
<!-- Please describe your changes on the following line: -->
Use bitflags for multikeyword properties
---
<!-- 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#15556
<!-- 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/15595)
<!-- Reviewable:end -->
