Add colorprofile destination

[noamr]

For CSS color-profiles
(https://drafts.csswg.org/css-color-4/#at-profile)

Uses style-src for CSP.

Closes #1324

• At least two implementers are interested (and none opposed):
  • …
  • …
• Tests are written and can be reviewed and commented upon at:
  • …
• Implementation bugs are filed:
  • Chrome: …
  • Firefox: …
  • Safari: …

(See WHATWG Working Mode: Changes for more details.)

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Preview | Diff

[annevk]

Modulo nit this looks good. Though as a follow-up the order of destinations in the table needs adjusting. It used to be lexicographical within a given initiator, but that got lost after some additions.

[annevk]

So I checked and as far as implementer interest this is kinda hard to assess as there are many other color features to tackle first. I guess we could add this mainly for registry purposes and consider it close to editorial.

@domenic @foolip thoughts?

[domenic]

Eh, I mean, it seems like you should be able to answer "are multiple implementations planning on fetching color profiles, or is fetching color profiles a single-browser idea/a CSSWG spec-fiction?"

I think we can relax the

The support from implementers should be of the form “we would like to implement this soon” and not just “this seems like a reasonable idea”.

request in this case since it's more of a registry/cross-spec integration issue. But it'd still be good to double-check that we're not putting something in that will never get implemented, or that supports a forever-single-vendor feature.

[annevk]

Fair. For Gecko it's something we'd probably consider implementing once we have all the other wide gamut features, but there isn't even a concrete half-float canvas API proposal yet, so it really seems quite far out there. And then I'm not sure to what extent the external color profile formats have been vetted. It certainly seems like the fetch pipeline has seen little attention. Do you know who to ask for Chromium? @smfr I guess color profiles are something you can comment on for WebKit?

[smfr]

I think I've stated in the past that Apple doesn't have any plans to implement color profile fetching. There are too many issues with asynchrony to work out.

[noamr]

Closing for now as color profiles are far from consensus at this point.