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

chrome/browser/chromeos/login/app_launch_controller.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/login/app_launch_controller.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/json/json_file_value_serializer.h"
@@ skipping 11 matching lines @@
 #include "chrome/browser/chromeos/login/ui/login_display_host_impl.h"
 #include "chrome/browser/chromeos/login/ui/oobe_display.h"
 #include "chrome/browser/chromeos/login/ui/webui_login_view.h"
 #include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/chromeos/login/app_launch_splash_screen_handler.h"
 #include "chrome/browser/ui/webui/chromeos/login/oobe_ui.h"
 #include "chromeos/settings/cros_settings_names.h"
+#include "components/user_manager/known_user.h"
 #include "components/user_manager/user_manager.h"
 #include "content/public/browser/notification_service.h"
 #include "extensions/browser/app_window/app_window.h"
 #include "extensions/browser/app_window/app_window_registry.h"
 #include "net/base/network_change_notifier.h"
 
 namespace chromeos {
 
 namespace {
 
@@ skipping 110 matching lines @@
     if (!CrosSettings::Get()->GetInteger(
             kAccountsPrefDeviceLocalAccountAutoLoginDelay, &delay)) {
       delay = 0;
     }
     DCHECK_EQ(0, delay) << "Kiosks do not support non-zero auto-login delays";
 
     // If we are launching a kiosk app with zero delay, mark it appropriately.
     if (delay == 0)
       KioskAppManager::Get()->SetAppWasAutoLaunchedWithZeroDelay(app_id_);
   }
-
   kiosk_profile_loader_.reset(
-      new KioskProfileLoader(app.user_id, false, this));
+      new KioskProfileLoader(app.account_id.GetUserEmail(), false, this));

[xiyuan, 2016/02/17 23:14:25]

Update KioskProfileLoader to take AccountId as well?

[Alexander Alekseev, 2016/02/18 13:45:14]

Done.

   kiosk_profile_loader_->Start();
 }
 
 // static
 void AppLaunchController::SkipSplashWaitForTesting() {
   skip_splash_wait_ = true;
 }
 
 // static
 void AppLaunchController::SetNetworkWaitForTesting(int wait_time_secs) {
@@ skipping 271 matching lines @@
   KioskAppLaunchError::Save(error);
   chrome::AttemptUserExit();
   CleanUp();
 }
 
 bool AppLaunchController::IsShowingNetworkConfigScreen() {
   return network_config_requested_;
 }
 
 }   // namespace chromeos