Re: [webcomponents] Need to update CSS Scoping for closed shadow tree (#293)

It looks we have to add one more action item: 

Making `::content` take only a *simple* selector, instead of a selector.

The current ability of `::content`, which can take a selector, makes the implementation of style engine harder. We'd like to simplify it.

We believe that a simple selector meets the requirements.

Quoted from the Polymer developer:

> Re: ​​`::content(selector)`, I am not sure how much this helps cascading per se. I am just suggesting that `::content`'s ability to target descendants is not necessary for us. We only need to style distributed children. If we *could* make that change to `::content`, it seems like there is opportunity to simplify the implementation.

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/webcomponents/issues/293#issuecomment-132458969