Paint holding

[kurtextrem]

As discussed in the WebPerfWG call, I'm just noting down the thoughts for public discussion.

I asked how the spec would treat painting / paint holding (e.g. during a navigation).
@noamr mentioned that is out of the scope for now (as this is more a primitive, so not related to navigations). So it would e.g. need a user land JS implementation that holds the paint (via CSS display:none or something), or using View Transitions for individual elements/nodes.

An idea I had was using the <link rel="expect" blocking="render" href="#id"> tag — which if inserted could hold paint until #id is also patched in.

[noamr]

Thanks for opening this!

It's a very good question and in scope for this repo, it was out of scope only in the context of the discussion about patching which was the topic at the WG meeting.