[csswg-drafts] [css-scoping-1] Drop :host-context (#3699)

rniwa has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-scoping-1] Drop :host-context ==
Splitting the discussion from https://github.com/w3c/csswg-drafts/issues/1915, as we've repeatedly said in the past, we don't think changing the style of an element based on where it appears is a good practice to design a re-usable element in general, and this particular feature poses a significant implementation complexity & cost as pointed out by @emilio in https://github.com/w3c/csswg-drafts/issues/1915#issuecomment-467590316.

We propose to drop this feature from the specification as we've previously requested.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/3699 using your GitHub account