Make Servo's rounding of image-orientation values agree with Gecko's, and pass orientations directly as an enum instead of as angles.
Has been reviewed: https://reviewboard.mozilla.org/r/155336/
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Bugzilla issue: https://bugzilla.mozilla.org/show_bug.cgi?id=1355380
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selectors: Avoid looking at MatchingMode if the selector isn't the topmost.
Also, switch the hover quirk to the same mechanism.
Bug: 1379696
Reviewed-By: bholley
MozReview-Commit-ID: KrmNqNyASf6
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Store font-weight as integer directly
It doesn't make much sense to store `font-weight` as separate enums, especially given that we would need to support (somehow) arbitrary font weight value when we implement CSS Fonts Level 4.
This PR refactors the `font-weight` a bit to make it store as `u16` directly.
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stylo: Fix font-variant-alternates property
`font-variant-alternates` was just parsing values as keywords. But many of the alternates are actually functions instead of keywords. This fixes that.
r=emilio on bugzilla side.
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- [X] These changes fix [Bug 1356124](https://bugzilla.mozilla.org/show_bug.cgi?id=1356124)
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