Fix the System Profile with extensions.

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 <algorithm>   // For max().
 #include <set>
 
 #include "apps/app_load_service.h"
@@ skipping 664 matching lines @@
     VLOG(2) << "ProcessCmdLineImpl: PLACE 6.A";
     // If the last used profile is locked or was a guest, show the user manager.
     if (switches::IsNewAvatarMenu()) {
       ProfileInfoCache& profile_info =
           g_browser_process->profile_manager()->GetProfileInfoCache();
       size_t profile_index = profile_info.GetIndexOfProfileWithPath(
           last_used_profile->GetPath());
       bool signin_required = profile_index != std::string::npos &&
           profile_info.ProfileIsSigninRequiredAtIndex(profile_index);
 
-      // Guest or locked profiles cannot be re-opened on startup. The only
-      // exception is if there's already a Guest window open in a separate
+      // Guest, system or locked profiles cannot be re-opened on startup. The
+      // only exception is if there's already a Guest window open in a separate
       // process (for example, launching a new browser after clicking on a
       // downloaded file in Guest mode).
-      bool has_guest_browsers = last_used_profile->IsGuestSession() &&
+      bool guest_or_system = last_used_profile->IsGuestSession() ||
+                             last_used_profile->IsSystemProfile();
+      bool has_guest_browsers = guest_or_system &&
           chrome::GetTotalBrowserCountForProfile(
               last_used_profile->GetOffTheRecordProfile()) > 0;

[msw, 2015/05/21 04:34:43]

Is GetOffTheRecordProfile safe to call for the system profile?

[Mike Lerman, 2015/05/21 15:27:31]

Don't see why not? the function just iterates over the BrowserList looking for
matching profiles, and ideally won't find any.

[msw, 2015/05/21 17:48:12]

Acknowledged.

-      if (signin_required ||
-          (last_used_profile->IsGuestSession() && !has_guest_browsers)) {
+      if (signin_required || (guest_or_system && !has_guest_browsers)) {
         profiles::UserManagerProfileSelected action =
             command_line.HasSwitch(switches::kShowAppList) ?
                 profiles::USER_MANAGER_SELECT_PROFILE_APP_LAUNCHER :
                 profiles::USER_MANAGER_SELECT_PROFILE_NO_ACTION;
         UserManager::Show(
             base::FilePath(), profiles::USER_MANAGER_NO_TUTORIAL, action);
         return true;
       }
     }
 
@@ skipping 145 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);
 }