[Chromedriver] Chromedriver should handle unexpected alert automatically.

chrome/test/chromedriver/chrome/chrome_desktop_impl.h

Index: chrome/test/chromedriver/chrome/chrome_desktop_impl.h
diff --git a/chrome/test/chromedriver/chrome/chrome_desktop_impl.h b/chrome/test/chromedriver/chrome/chrome_desktop_impl.h
index 8923d54029f0750c6310552ed03776677f572a1d..016cde74de6cb32cb9f5fd2ba37a912f9e1df2e5 100644
--- a/chrome/test/chromedriver/chrome/chrome_desktop_impl.h
+++ b/chrome/test/chromedriver/chrome/chrome_desktop_impl.h
@@ -31,6 +31,7 @@ class ChromeDesktopImpl : public ChromeImpl {
       std::unique_ptr<DevToolsClient> websocket_client,
       ScopedVector<DevToolsEventListener>& devtools_event_listeners,
       std::unique_ptr<PortReservation> port_reservation,
+      std::string unexpected_alert_behaviour,
       std::string page_load_strategy,
       base::Process process,
       const base::CommandLine& command,