factory constructor KeyboardEvent

Source

factory KeyboardEvent(String type,
    {Window view,
    bool canBubble: true,
    bool cancelable: true,
    int location,
    int keyLocation, // Legacy alias for location
    bool ctrlKey: false,
    bool altKey: false,
    bool shiftKey: false,
    bool metaKey: false}) {
  if (view == null) {
    view = window;
  }
  location ??= keyLocation ?? 1;
  final e = document._createEvent("KeyboardEvent");
  e._initKeyboardEvent(type, canBubble, cancelable, view, "", location,
      ctrlKey, altKey, shiftKey, metaKey);
  return e;
}