[Chromedriver] Chromedriver should handle unexpected alert automatically.

chrome/test/chromedriver/session_commands.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/test/chromedriver/session_commands.h"
 
 #include <list>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 109 matching lines @@
   caps->SetBoolean("mobileEmulationEnabled",
                    chrome->IsMobileEmulationEnabled());
   caps->SetBoolean("applicationCacheEnabled", false);
   caps->SetBoolean("browserConnectionEnabled", false);
   caps->SetBoolean("cssSelectorsEnabled", true);
   caps->SetBoolean("webStorageEnabled", true);
   caps->SetBoolean("rotatable", false);
   caps->SetBoolean("acceptSslCerts", true);
   caps->SetBoolean("nativeEvents", true);
   caps->SetBoolean("hasTouchScreen", chrome->HasTouchScreen());
+  caps->SetString("unexpectedAlertBehaviour",
+                   chrome->UnexpectedAlertBehaviour());
 
   ChromeDesktopImpl* desktop = NULL;
   Status status = chrome->GetAsDesktop(&desktop);
   if (status.IsOk()) {
     caps->SetString("chrome.userDataDir",
                     desktop->command().GetSwitchValueNative("user-data-dir"));
     caps->SetBoolean("networkConnectionEnabled",
                      desktop->IsNetworkConnectionEnabled());
   }
 
@@ skipping 734 matching lines @@
                                       std::unique_ptr<base::Value>* value) {
   WebView* web_view = nullptr;
   Status status = session->GetTargetWindow(&web_view);
   if (status.IsError())
     return status;
   status = web_view->DeleteScreenOrientation();
   if (status.IsError())
     return status;
   return Status(kOk);
 }