Lock only permitted where a supervised user is or was.

chrome/common/pref_names.h

 // 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.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 
 #include <stddef.h>
@@ skipping 357 matching lines @@
 extern const char kProfileAvatarTutorialShown[];
 
 extern const char kInvertNotificationShown[];
 
 extern const char kPrintingEnabled[];
 extern const char kPrintPreviewDisabled[];
 
 extern const char kDefaultSupervisedUserFilteringBehavior[];
 
 extern const char kSupervisedUserCreationAllowed[];
+extern const char kSupervisedUserExistsOrExisted[];
 extern const char kSupervisedUsers[];
 
 extern const char kProfileResetPromptMementoInProfilePrefs[];
 
 extern const char kMessageCenterDisabledExtensionIds[];
 extern const char kMessageCenterDisabledSystemComponentIds[];
 extern const char kWelcomeNotificationDismissed[];
 extern const char kWelcomeNotificationDismissedLocal[];
 extern const char kWelcomeNotificationPreviouslyPoppedUp[];
 extern const char kWelcomeNotificationExpirationTimestamp[];
@@ skipping 427 matching lines @@
 
 extern const char kQuickCheckEnabled[];
 extern const char kBrowserGuestModeEnabled[];
 extern const char kBrowserAddPersonEnabled[];
 
 extern const char kEasyUnlockHardlockState[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_