virtual void Visit(CefRefPtr<CefDOMDocument> document)
{
// Register an click listener for the button.
CefRefPtr<CefDOMNode> button = document->GetElementById("button");
ASSERT(button.get());
button->AddEventListener("click", new Listener(), false);
}
void RegisterClickListener(CefRefPtr<CefDOMDocument> document,
CefRefPtr<CefDOMEventListener> listener,
const std::string& elementId)
{
CefRefPtr<CefDOMNode> element = document->GetElementById(elementId);
ASSERT(element.get());
element->AddEventListener("click", listener, false);
}