CompositionEvent 构造函数

实现

factory CompositionEvent(String type,
    {bool canBubble = false,
    bool cancelable = false,
    Window? view,
    String? data,
    String? locale}) {
  if (view == null) {
    view = window;
  }
  CompositionEvent e =
      document._createEvent("CompositionEvent") as CompositionEvent;

  if (Device.isFirefox) {
    // Firefox requires the locale parameter that isn't supported elsewhere.
    JS('void', '#.initCompositionEvent(#, #, #, #, #, #)', e, type, canBubble,
        cancelable, view, data, locale);
  } else {
    e._initCompositionEvent(type, canBubble, cancelable, view, data);
  }

  return e;
}