1. DomName('Performance.mark')
  2. DocsEditable()
  3. Experimental()
void mark(String markName)

Source 

@DomName('Performance.mark')
@DocsEditable()
// https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/UserTiming/Overview.html#extensions-performance-interface
@Experimental()
void mark(String markName) => _blink.BlinkPerformance.instance.mark_Callback_1_(this, markName);