[Chromedriver] Chromedriver should handle unexpected alert automatically.

chrome/test/chromedriver/chrome_launcher.cc

Index: chrome/test/chromedriver/chrome_launcher.cc
diff --git a/chrome/test/chromedriver/chrome_launcher.cc b/chrome/test/chromedriver/chrome_launcher.cc
index b4ac72d017abb0eb7d1416e1803ef90d6247a1f2..963af5b057123bc6db0017f6a49077746d34a22d 100644
--- a/chrome/test/chromedriver/chrome_launcher.cc
+++ b/chrome/test/chromedriver/chrome_launcher.cc
@@ -307,6 +307,7 @@ Status LaunchRemoteChromeSession(
   chrome->reset(new ChromeRemoteImpl(std::move(devtools_http_client),
                                      std::move(devtools_websocket_client),
                                      *devtools_event_listeners,
+                                     capabilities.unexpected_alert_behaviour,
                                      capabilities.page_load_strategy));
   return Status(kOk);
 }
@@ -446,6 +447,7 @@ Status LaunchDesktopChrome(
                             std::move(devtools_websocket_client),
                             *devtools_event_listeners,
                             std::move(port_reservation),
+                            capabilities.unexpected_alert_behaviour,
                             capabilities.page_load_strategy,
                             std::move(process),
                             command,
@@ -530,6 +532,7 @@ Status LaunchAndroidChrome(
                                       std::move(devtools_websocket_client),
                                       *devtools_event_listeners,
                                       std::move(port_reservation),
+                                      capabilities.unexpected_alert_behaviour,
                                       capabilities.page_load_strategy,
                                       std::move(device)));
   return Status(kOk);