[cros mp] Load profiles from /home/chronos/u-[$hash], add GetUserIdHashFromProfile()

chrome/browser/chromeos/app_mode/kiosk_app_launcher.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_app_launcher.h"
 
 #include "base/chromeos/chromeos_version.h"
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
@@ skipping 95 matching lines @@
  public:
   explicit ProfileLoader(KioskAppLauncher* launcher)
       : launcher_(launcher) {
   }
 
   virtual ~ProfileLoader() {
     LoginUtils::Get()->DelegateDeleted(this);
   }
 
   void Start() {
-    // TODO(nkostylev): Pass real username_hash here.
+    // TODO(nkostylev): Pass real username_hash here. crbug.com/238985
     LoginUtils::Get()->PrepareProfile(
         UserContext(GetAppUserNameFromAppId(launcher_->app_id_),
                     std::string(),   // password
                     std::string()),  // auth_code
         std::string(),  // display email
         false,  // using_oauth
         false,  // has_cookies
         this);
   }
 
@@ skipping 104 matching lines @@
   (new chromeos::StartupAppLauncher(profile, app_id_))->Start();
 
   if (LoginDisplayHostImpl::default_host())
     LoginDisplayHostImpl::default_host()->OnSessionStart();
   UserManager::Get()->SessionStarted();
 
   ReportLaunchResult(KioskAppLaunchError::NONE);
 }
 
 }  // namespace chromeos