[css-scoping] Combining :host-context and :host selector

Hey,

I was wondering if anyone has some exact information if the following css selector is allowed:

<style>
  :host-context(.blocky):host(:hover) {
    display: block;
    background: red;
  }
</style>

Chrome handles the selector correctly.
An example can be found here: http://jsbin.com/diburokino/1/edit?html,output

Regards,
Steve