bool Shell::IsSystemModalWindowOpen() const {
  if (simulate_modal_window_open_for_testing_)
    return true;
  const std::vector<aura::Window*> containers = GetContainersFromAllRootWindows(
      kShellWindowId_SystemModalContainer, nullptr);
  for (std::vector<aura::Window*>::const_iterator cit = containers.begin();
       cit != containers.end(); ++cit) {
    for (aura::Window::Windows::const_iterator wit = (*cit)->children().begin();
         wit != (*cit)->children().end(); ++wit) {
      if ((*wit)->GetProperty(aura::client::kModalKey) ==
          ui::MODAL_TYPE_SYSTEM && (*wit)->TargetVisibility()) {
        return true;
      }
    }
  }
  return false;
}

Unknown