Add new BrowserForceSigninEnabeld policy option with future:true flag.

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 772 matching lines @@
 extern const char kWatchdogExtensionActive[];
 
 #if BUILDFLAG(ANDROID_JAVA_UI)
 extern const char kPartnerBookmarkMappings[];
 #endif
 
 extern const char kQuickCheckEnabled[];
 extern const char kPacHttpsUrlStrippingEnabled[];
 extern const char kBrowserGuestModeEnabled[];
 extern const char kBrowserAddPersonEnabled[];
+extern const char kBrowserForceSigninEnabled[];
 
 extern const char kEasyUnlockDeviceId[];
 extern const char kEasyUnlockHardlockState[];
 extern const char kEasyUnlockLocalStateTpmKeys[];
 extern const char kEasyUnlockLocalStateUserPrefs[];
 
 extern const char kRecoveryComponentNeedsElevation[];
 
 extern const char kRegisteredSupervisedUserWhitelists[];
 
@@ skipping 23 matching lines @@
 #endif
 
 extern const char kOriginTrialPublicKey[];
 extern const char kOriginTrialDisabledFeatures[];
 
 extern const char kComponentUpdatesEnabled[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_