Enable new sign in flow for E2E tests.

chrome/browser/ui/webui/signin/login_ui_test_utils.h

 // Copyright 2014 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_SIGNIN_LOGIN_UI_TEST_UTILS_H_
 #define CHROME_BROWSER_UI_WEBUI_SIGNIN_LOGIN_UI_TEST_UTILS_H_
 
 #include <string>
 
 class Browser;
 
 namespace login_ui_test_utils {
 
 // Blocks until the login UI is available and ready for authorization.
 void WaitUntilUIReady(Browser* browser);
 
+// Blocks until an element with id |element_id| exists in the signin page.
+void WaitUntilElementExistsInSigninFrame(Browser* browser,
+                                         const std::string& element_id);
+
+// Returns whether an element with id |element_id| exists in the signin page.
+bool ElementExistsInSigninFrame(Browser* browser,
+                                const std::string& element_id);
+
 // Executes JavaScript code to sign in a user with email and password to the
-// auth iframe hosted by gaia_auth extension.
+// auth iframe hosted by gaia_auth extension. This function automatically
+// detects the version of GAIA sign in page to use.
 void ExecuteJsToSigninInSigninFrame(Browser* browser,
                                     const std::string& email,
                                     const std::string& password);
 
+// Executes JS to sign in the user in the new GAIA sign in flow.
+void SigninInNewGaiaFlow(Browser* browser,
+                         const std::string& email,
+                         const std::string& password);
+
+// Executes JS to sign in the user in the old GAIA sign in flow.
+void SigninInOldGaiaFlow(Browser* browser,
+                         const std::string& email,
+                         const std::string& password);
+
 // A function to sign in a user using Chrome sign-in UI interface.
 // This will block until a signin succeeded or failed notification is observed.
 bool SignInWithUI(Browser* browser,
                   const std::string& email,
                   const std::string& password);
 
 }  // namespace login_ui_test_utils
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SIGNIN_LOGIN_UI_TEST_UTILS_H_