[css-paint-api]: APIs not exposed in Worklets

[annevk]

It seems we want the interfaces in https://drafts.css-houdini.org/css-typed-om/ to be exposed in Worklets, right?

@bzbarsky

[bfgeek]

Needs to be exposed only to 'PaintWorklet' not the more generic 'Worklet'

(exposing this to 'AudioWorklet' won't make sense).

[annevk]

Yeah, presumably they'll be added to other CSS worklets too, but I suppose you can refactor when that happens.

[shans]

I don't think there needs to be any specific spec text in css-typed-om to support this, so I'm removing the typed-om tag.

[bfgeek]

This needs the [Exposed=PaintWorklet] annotation in the typed-om spec for all the things we want exposed there.

[shans]

Can you provide a list of the things you want exposed?

[bfgeek]

CSSStyleValue and of the sub-classes, e.g. CSSKeywordValue etc.
CSSTransformComponent and sub-classes.
StylePropertyMapReadOnly (...no need for StylePropertyMap).

There is the open question of #238 as well.

[shans]

We resolved in #238 not to expose constructors and parse methods. I think that contradicts this issue?