Fix#16165.
Also, it turns out that the CSSFontFaceRule IDL specified in the css-fonts spec is not web-compatible. Instead browsers implement a .style attribute like in CSSStyleRule: https://github.com/w3c/csswg-drafts/issues/825
This in turn requires preserving data about which descriptors were set or not (distinguishing unset from set to a value that happens to be the initial value), so this commit also makes every field `Option<_>`.
Source-Repo: https://github.com/servo/servo
Source-Revision: fac0d17fd6edf996876d6e6379e48ef4f9cb43d6
This PR is intended to add basic support for all CSSOM interfaces, with the ability to index `document.styleSheets` and css rule lists, and serializing individual css rules. Handling individual interface methods for CSSRule subclasses can probably be done with easy/medium bugs.
Mutation safety isn't dealt with here; if the css rule list is mutated the CSSOM will be in an inconsistent state. I intend to deal with this via zero sized tokens, see https://groups.google.com/forum/#!topic/mozilla.dev.servo/AnxJoVmtMXQ . I'll handle that when I start making the CSSOM mutable. (Getting the immutable bit landed first opens this up for easy bugs)
This doesn't really change style aside from adding an extra arc in the CSS rule list as discussed in the linked thread. So far this same design can be used by stylo as well when the time comes.
f? @SimonSapin @emilio
cc @upsuper
part of #11420
Todo:
- [x] Stubs for rest of the CSSRule subclasses
- [x] <s>ToCSS impls for CSSRules.</s> May make into easy bugs and stub out in this PR https://github.com/servo/servo/issues/14195
- [x] Cache CSSStyleSheet on the relevant node
Source-Repo: https://github.com/servo/servo
Source-Revision: afc60bee2809059b8b754a1c6d6d10c1d36326fb
