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

chrome/browser/chromeos/app_mode/kiosk_profile_loader.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/chromeos/app_mode/kiosk_profile_loader.h"
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 101 matching lines @@
   KioskProfileLoader* loader_;
   int retry_count_;
 
   DISALLOW_COPY_AND_ASSIGN(CryptohomedChecker);
 };
 
 
 ////////////////////////////////////////////////////////////////////////////////
 // KioskProfileLoader
 
-KioskProfileLoader::KioskProfileLoader(const std::string& app_user_id,
+KioskProfileLoader::KioskProfileLoader(const AccountId& app_account_id,
                                        bool use_guest_mount,
                                        Delegate* delegate)
-    : user_id_(app_user_id),
+    : account_id_(app_account_id),
       use_guest_mount_(use_guest_mount),
       delegate_(delegate) {}
 
 KioskProfileLoader::~KioskProfileLoader() {}
 
 void KioskProfileLoader::Start() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   login_performer_.reset();
   cryptohomed_checker_.reset(new CryptohomedChecker(this));
   cryptohomed_checker_->StartCheck();
 }
 
 void KioskProfileLoader::LoginAsKioskAccount() {
   login_performer_.reset(new ChromeLoginPerformer(this));
-  login_performer_->LoginAsKioskAccount(user_id_, use_guest_mount_);
+  login_performer_->LoginAsKioskAccount(account_id_, use_guest_mount_);
 }
 
 void KioskProfileLoader::ReportLaunchResult(KioskAppLaunchError::Error error) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   if (error != KioskAppLaunchError::NONE) {
     delegate_->OnProfileLoadFailed(error);
   }
 }
 
 void KioskProfileLoader::OnAuthSuccess(const UserContext& user_context) {
   // LoginPerformer will delete itself.
   login_performer_->set_delegate(NULL);
   ignore_result(login_performer_.release());
 
   // If we are launching a demo session, we need to start MountGuest with the
   // guest username; this is because there are several places in the cros code
   // which rely on the username sent to cryptohome to be $guest. Back in Chrome
   // we switch this back to the demo user name to correctly identify this
   // user as a demo user.
   UserContext context = user_context;
   if (context.GetAccountId() == login::GuestAccountId())
-    context.SetUserID(login::DemoAccountId().GetUserEmail());
+    context.SetAccountId(login::DemoAccountId());
   UserSessionManager::GetInstance()->StartSession(
       context, UserSessionManager::PRIMARY_USER_SESSION,
       false,  // has_auth_cookies
       false,  // Start session for user.
       this);
 }
 
 void KioskProfileLoader::OnAuthFailure(const AuthFailure& error) {
   ReportLaunchResult(LoginFailureToKioskAppLaunchError(error));
 }
@@ skipping 14 matching lines @@
                                            bool browser_launched) {
   // This object could be deleted any time after successfully reporting
   // a profile load, so invalidate the delegate now.
   UserSessionManager::GetInstance()->DelegateDeleted(this);
 
   delegate_->OnProfileLoaded(profile);
   ReportLaunchResult(KioskAppLaunchError::NONE);
 }
 
 }  // namespace chromeos