1. DomName('CSSGroupingRule.insertRule')
  2. DocsEditable()
  3. Experimental()
int insertRule(String rule, int index)

Source 

@DomName('CSSGroupingRule.insertRule')
@DocsEditable()
@Experimental() // untriaged
int insertRule(String rule, int index) => _blink.BlinkCSSGroupingRule.instance.insertRule_Callback_2_(this, rule, index);