[ShadyCSS] :host() selector containing multiple elements extremely slow when first element has a long name

[eriklumme]

Complete example

<link rel="import" href="../polymer/polymer-element.html">

<dom-module id="theme-bug">
  <template>
    <style>
      :host(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, a) {
      }
    </style>
  </template>

  <script>
    class ThemeBug extends Polymer.Element {
      static get is() { return 'theme-bug'; }
    }

    window.customElements.define(ThemeBug.is, ThemeBug);
  </script>
</dom-module>

When there are two elements within :host(), and the length of the first gets to around 20-30 characters, the page loading time gets slow to the point that e.g. Firefox freezes completely.

If the order of the long and short names are reversed, this is not an issue.

[stale]

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[stale]

This issue has been automatically closed after being marked stale. If you're still facing this problem with the above solution, please comment and we'll reopen!