ChromeOS cryptohome should be able to use gaia id as user identifier.

chrome/browser/chromeos/policy/device_local_account_browsertest.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/browser/chromeos/policy/device_local_account.h"
 
 #include <stddef.h>
 #include <map>
 #include <set>
 #include <string>
@@ skipping 713 matching lines @@
     // Start login into the device-local account.
     chromeos::LoginDisplayHost* host =
         chromeos::LoginDisplayHost::default_host();
     ASSERT_TRUE(host);
     host->StartSignInScreen(LoginScreenContext());
     chromeos::ExistingUserController* controller =
         chromeos::ExistingUserController::current_controller();
     ASSERT_TRUE(controller);
 
     chromeos::UserContext user_context(user_manager::USER_TYPE_PUBLIC_ACCOUNT,
-                                       account_id_1_.GetUserEmail());
+                                       account_id_1_);
     user_context.SetPublicSessionLocale(locale);
     user_context.SetPublicSessionInputMethod(input_method);
     controller->Login(user_context, chromeos::SigninSpecifics());
   }
 
   void WaitForSessionStart() {
     if (IsSessionStarted())
       return;
     content::WindowedNotificationObserver(chrome::NOTIFICATION_SESSION_STARTED,
                                           base::Bind(IsSessionStarted)).Wait();
@@ skipping 1686 matching lines @@
   ASSERT_TRUE(content::ExecuteScript(contents_,
                                      "$('tos-accept-button').click();"));
 
   WaitForSessionStart();
 }
 
 INSTANTIATE_TEST_CASE_P(TermsOfServiceDownloadTestInstance,
                         TermsOfServiceDownloadTest, testing::Bool());
 
 }  // namespace policy