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

chrome/browser/ui/startup/startup_browser_creator.cc

 // Copyright (c) 2012 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/startup/startup_browser_creator.h"
 
 #include <stddef.h>
 
 #include <algorithm>   // For max().
 #include <set>
@@ skipping 654 matching lines @@
         last_used_profile,
         command_line.GetSwitchValueASCII(switches::kAppId));
 
     // Skip browser launch since app mode launches its app window.
     silent_launch = true;
   }
 
   // If we are a demo app session and we crashed, there is no safe recovery
   // possible. We should instead cleanly exit and go back to the OOBE screen,
   // where we will launch again after the timeout has expired.
+  //
+  // TODO (alemate): kLoginUser value is no longer user e-mail. Make this check
+  // more correct.
   if (chromeos::DemoAppLauncher::IsDemoAppSession(
       command_line.GetSwitchValueASCII(chromeos::switches::kLoginUser))) {
     chrome::AttemptUserExit();
     return false;
   }
 #endif  // OS_CHROMEOS
 
 #if defined(TOOLKIT_VIEWS) && defined(USE_X11)
   ui::TouchFactory::SetTouchDeviceListFromCommandLine();
 #endif
@@ skipping 246 matching lines @@
   // If we are showing the app list then chrome isn't shown so load the app
   // list's profile rather than chrome's.
   if (command_line.HasSwitch(switches::kShowAppList)) {
     return AppListService::Get(chrome::HOST_DESKTOP_TYPE_NATIVE)->
         GetProfilePath(user_data_dir);
   }
 
   return g_browser_process->profile_manager()->GetLastUsedProfileDir(
       user_data_dir);
 }