Lock only permitted where a supervised user is or was.

chrome/browser/profiles/profiles_state.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/profiles/profiles_state.h"
 
 #include "base/files/file_path.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 27 matching lines @@
   default_profile_dir =
       default_profile_dir.AppendASCII(chrome::kInitialProfile);
   return default_profile_dir;
 }
 
 void RegisterPrefs(PrefRegistrySimple* registry) {
   // Preferences about global profile information.
   registry->RegisterStringPref(prefs::kProfileLastUsed, std::string());
   registry->RegisterIntegerPref(prefs::kProfilesNumCreated, 1);
   registry->RegisterListPref(prefs::kProfilesLastActive);
+  registry->RegisterBooleanPref(prefs::kSupervisedUserExistsOrExisted, false);
 
   // Preferences about the user manager.
   registry->RegisterBooleanPref(prefs::kBrowserGuestModeEnabled, true);
   registry->RegisterBooleanPref(prefs::kBrowserAddPersonEnabled, true);
 }
 
 base::string16 GetAvatarNameForProfile(const base::FilePath& profile_path) {
   base::string16 display_name;
 
   if (profile_path == ProfileManager::GetGuestProfilePath()) {
@@ skipping 133 matching lines @@
   DCHECK(guest_profile);
 
   PrefService* local_state = g_browser_process->local_state();
   DCHECK(local_state);
   local_state->SetString(prefs::kProfileLastUsed,
                          guest_profile->GetPath().BaseName().MaybeAsASCII());
   return guest_profile;
 }
 
 }  // namespace profiles