We should use UserID object to identify users instead of username.

chrome/browser/extensions/api/autotest_private/autotest_private_api.cc

 // Copyright (c) 2012 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/browser/extensions/api/autotest_private/autotest_private_api.h"
 
 #include "base/lazy_instance.h"
 #include "base/strings/string_number_conversions.h"
 #include "chrome/browser/extensions/extension_action_manager.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ skipping 95 matching lines @@
     result->SetBoolean("isLoggedIn", user_manager->IsUserLoggedIn());
     result->SetBoolean("isOwner", user_manager->IsCurrentUserOwner());
     result->SetBoolean("isScreenLocked", is_screen_locked);
     if (user_manager->IsUserLoggedIn()) {
       result->SetBoolean("isRegularUser",
                          user_manager->IsLoggedInAsUserWithGaiaAccount());
       result->SetBoolean("isGuest", user_manager->IsLoggedInAsGuest());
       result->SetBoolean("isKiosk", user_manager->IsLoggedInAsKioskApp());
 
       const user_manager::User* user = user_manager->GetLoggedInUser();
-      result->SetString("email", user->email());
+      result->SetString("email", user->GetUserID().GetUserEmail());
       result->SetString("displayEmail", user->display_email());
 
       std::string user_image;
       switch (user->image_index()) {
         case user_manager::User::USER_IMAGE_EXTERNAL:
           user_image = "file";
           break;
 
         case user_manager::User::USER_IMAGE_PROFILE:
           user_image = "profile";
@@ skipping 210 matching lines @@
   return new AutotestPrivateAPI();
 }
 
 AutotestPrivateAPI::AutotestPrivateAPI() : test_mode_(false) {
 }
 
 AutotestPrivateAPI::~AutotestPrivateAPI() {
 }
 
 }  // namespace extensions