This CL replaces user_manager::UserID with AccountId.

chrome/browser/ui/ash/multi_user/multi_user_context_menu_chromeos.cc

 // Copyright 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/browser/ui/ash/multi_user/multi_user_context_menu.h"
 
 #include "ash/multi_profile_uma.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_util.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_warning_dialog.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/grit/generated_resources.h"
+#include "components/signin/core/account_id/account_id.h"
 #include "components/user_manager/user.h"
 #include "components/user_manager/user_manager.h"
 #include "ui/aura/window.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/models/simple_menu_model.h"
 
 namespace chromeos {
 
 namespace {
 
@@ skipping 80 matching lines @@
   switch (command_id) {
     case IDC_VISIT_DESKTOP_OF_LRU_USER_2:
     case IDC_VISIT_DESKTOP_OF_LRU_USER_3: {
       // When running the multi user mode on Chrome OS, windows can "visit"
       // another user's desktop.
       const std::string& user_id =
           ash::Shell::GetInstance()
               ->session_state_delegate()
               ->GetUserInfo(IDC_VISIT_DESKTOP_OF_LRU_USER_2 == command_id ? 1
                                                                           : 2)
-              ->GetUserID();
+              ->GetUserID()
+              .GetUserEmail();
       base::Callback<void(bool)> on_accept =
           base::Bind(&OnAcceptTeleportWarning, user_id, window);

[stevenjb, 2015/10/22 17:52:36]

I would change OnAcceptTeleportWarning to take an AccountId since ideally we
will eventually change SetWindowForUser to take AccountId instead of a string
anyway.

[Alexander Alekseev, 2015/10/23 09:11:23]

Done.

 
       // Don't show warning dialog if any logged in user in multi-profiles
       // session dismissed it.
       const user_manager::UserList logged_in_users =
           user_manager::UserManager::Get()->GetLoggedInUsers();
       for (user_manager::UserList::const_iterator it = logged_in_users.begin();
            it != logged_in_users.end();
            ++it) {
         if (multi_user_util::GetProfileFromUserID(
             multi_user_util::GetUserIDFromEmail((*it)->email()))->GetPrefs()->
             GetBoolean(prefs::kMultiProfileWarningShowDismissed)) {
           bool active_user_show_option =
               ProfileManager::GetActiveUserProfile()->
               GetPrefs()->GetBoolean(prefs::kMultiProfileWarningShowDismissed);
           on_accept.Run(active_user_show_option);
           return;
         }
       }
       chromeos::ShowMultiprofilesWarningDialog(on_accept);
       return;
     }
     default:
       NOTREACHED();
   }
 }