Re: [csswg-drafts] [css-scoping-1] Specificity of :host, ::slotted, and :host-context doesn't seem to be defined? (#1915)

The CSS Working Group just discussed `:host-context`.

<details><summary>The full IRC log of that discussion</summary>
&lt;emilio> Topic: :host-context<br>
&lt;emilio> github: https://github.com/w3c/csswg-drafts/issues/1915<br>
&lt;fantasai> emilio: When looking into this stuff, what I didn't implement which Apple also doesn't, is because it's really slow<br>
&lt;fantasai> emilio: Reason why it's really slow is that for every class change, you either need to store everything for the whoel docuemnt, or you need to look at every shadow root that has a host context selector, and go through all the shadow roots inside your subtree to check if they have a relevant host-context rule...<br>
&lt;fantasai> emilio: Handling DOM changes when host-context selectors are involved<br>
&lt;fantasai> emilio: Blink solves this by doing subtree restyles?<br>
&lt;fantasai> futhark: So in Blink we aggregate style info at the docuemnt scope for everything<br>
&lt;fantasai> futhark: we don't use subtree calc<br>
&lt;fantasai> futhark: We invalidate inside the shadow root<br>
&lt;fantasai> futhark: We use a flag for it<br>
&lt;fantasai> emilio: One of the nice things in our impl is that the style info inside the shadow root is contained<br>
&lt;fantasai> emilio: Blink wants to make such a change, too<br>
&lt;fantasai> emilio: So effectively it's similarly slow as /deep/<br>
&lt;fantasai> emilio: Since I haven't seen anything in Bugzilla requesting it<br>
&lt;fantasai> emilio: And WebKit also hasn't implemented<br>
&lt;fantasai> emilio: So would like to drop<br>
&lt;fantasai> futhark: I don't have the usage numbers...<br>
&lt;fantasai> TabAtkins: We should see if it's used<br>
&lt;fantasai> TabAtkins: It offers a useful functionality but if ppl aren't suing it, I"m fine with dropping it<br>
&lt;fantasai> Rossen: So, collect data, come back and based on this we can move forward<br>
&lt;fantasai> fantasai: So maybe flag for next F2F so we don't forget<br>
&lt;fantasai> Rossen: Hope to get to it before<br>
</details>


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Received on Tuesday, 26 February 2019 19:59:52 UTC