gistfile1.txt

  Document::PopoverStack& popover_auto_stack = document.PopoverAutoStack();
  auto submenu_it = std::ranges::find(popover_auto_stack, sub_menu_);
  if (submenu_it == popover_auto_stack.end()) {
    // Our submenu is no longer open.
    Finish();
    return;
  }

  if (std::ranges::any_of(
          base::span(submenu_it, popover_auto_stack.end()).subspan<1>(),
          [](HTMLElement* e) -> bool { return IsA<HTMLMenuListElement>(e); })) {
    // There is another menu open, on top of our submenu in the popover stack.
    // The innermost submenu is the only one that should have a safe triangle.
    Finish();
    return;
  }