1. @DomName('Window.getMatchedCSSRules')
  2. @DocsEditable()
  3. @Experimental()
List<CssRule> getMatchedCssRules(Element element, String pseudoElement)

Returns all CSS rules that apply to the element's pseudo-element.

Source 

@DomName('Window.getMatchedCSSRules')
@DocsEditable()
@Experimental() // non-standard
List<CssRule> getMatchedCssRules(Element element, String pseudoElement) =>
    _blink.BlinkWindow.instance
        .getMatchedCSSRules_Callback_2_(this, element, pseudoElement);