Need to decide on how to handle pseudo-elements

[cbiesinger]

With render-subtree now a CSS property, it can be set on things that are not DOM elements. For example, ::before or ::marker and others.

I think most of that will work fine but we need to think through this, especially if we want to not support it on certain pseudo-elements (maybe ::selection), and if we fire activation events, what elements to fire them on for such cases.

[chrishtr]

Are there any pseudo-elements we do want to support render-subtree on? The whole point is to avoid rendering the subtree, not the current (pseudo-)element.

[cbiesinger]

Well, some pseudo-elements can have children (::before { content: "foo"; }), but sure, we could just define them all to ignore this.