Always load signin profile on Chrome OS startup.

chrome/browser/profiles/profile_manager.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/profiles/profile_manager.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 791 matching lines @@
   }
 
   if (!profile->GetPrefs()->HasPrefPath(prefs::kProfileAvatarIndex))
     profile->GetPrefs()->SetInteger(prefs::kProfileAvatarIndex, avatar_index);
 
   if (!profile->GetPrefs()->HasPrefPath(prefs::kProfileName))
     profile->GetPrefs()->SetString(prefs::kProfileName, profile_name);
 
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   bool force_supervised_user_id =
+#if defined(OS_CHROMEOS)
+      g_browser_process->platform_part()
+              ->profile_helper()
+              ->GetSigninProfileDir() != profile->GetPath() &&
+#endif
       command_line->HasSwitch(switches::kSupervisedUserId);
   if (force_supervised_user_id) {
     supervised_user_id =
         command_line->GetSwitchValueASCII(switches::kSupervisedUserId);
   }
   if (force_supervised_user_id ||
       !profile->GetPrefs()->HasPrefPath(prefs::kSupervisedUserId)) {
     profile->GetPrefs()->SetString(prefs::kSupervisedUserId,
                                    supervised_user_id);
   }
@@ skipping 546 matching lines @@
           last_non_supervised_profile_path.BaseName().MaybeAsASCII());
       FinishDeletingProfile(profile_to_delete_path);
     }
   }
 }
 #endif
 
 ProfileManagerWithoutInit::ProfileManagerWithoutInit(
     const base::FilePath& user_data_dir) : ProfileManager(user_data_dir) {
 }