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

chrome/browser/chromeos/app_mode/app_session.cc

 // Copyright 2015 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/app_session.h"
 
 #include <errno.h>
 #include <signal.h>
 
 #include "base/bind.h"
@@ skipping 102 matching lines @@
   }
 
  private:
   // extensions::AppWindowRegistry::Observer overrides:
   void OnAppWindowAdded(AppWindow* app_window) override {
     app_session_->OnAppWindowAdded(app_window);
   }
 
   void OnAppWindowRemoved(AppWindow* app_window) override {
     if (window_registry_->GetAppWindowsForApp(app_id_).empty()) {
-      if (DemoAppLauncher::IsDemoAppSession(
-              user_manager::UserManager::Get()->GetActiveUser()->email())) {
+      if (DemoAppLauncher::IsDemoAppSession(user_manager::UserManager::Get()
+                                                ->GetActiveUser()
+                                                ->GetAccountId())) {
         // If we were in demo mode, we disabled all our network technologies,
         // re-enable them.
         NetworkStateHandler* handler =
             NetworkHandler::Get()->network_state_handler();
         handler->SetTechnologyEnabled(
             NetworkTypePattern::NonVirtual(),
             true,
             chromeos::network_handler::ErrorCallback());
       }
       app_session_->OnLastAppWindowClosed();
@@ skipping 46 matching lines @@
   app_window_handler_.reset(new AppWindowHandler(this));
   app_window_handler_->Init(profile, app_id);
 
   browser_window_handler_.reset(new BrowserWindowHandler);
 
   plugin_handler_.reset(new KioskSessionPluginHandler(this));
 
   // For a demo app, we don't need to either setup the update service or
   // the idle app name notification.
   if (DemoAppLauncher::IsDemoAppSession(
-          user_manager::UserManager::Get()->GetActiveUser()->email()))
+          user_manager::UserManager::Get()->GetActiveUser()->GetAccountId()))
     return;
 
   // Set the app_id for the current instance of KioskAppUpdateService.
   KioskAppUpdateService* update_service =
       KioskAppUpdateServiceFactory::GetForProfile(profile);
   DCHECK(update_service);
   if (update_service)
     update_service->Init(app_id);
 
   // Start to monitor external update from usb stick.
@@ skipping 58 matching lines @@
     return;
   is_shutting_down_ = true;
 
   LOG(ERROR) << "Plugin hung detected. Dump and reboot.";
   content::BrowserThread::PostTask(
       content::BrowserThread::IO, FROM_HERE,
       base::Bind(&DumpPluginProcessOnIOThread, hung_plugins));
 }
 
 }  // namespace chromeos