Remove migration of obsolete value for "session.restore_on_startup".

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>
 
 #include "build/build_config.h"
 #include "chrome/common/features.h"
 
 namespace prefs {
 
 // Profile prefs. Please add Local State prefs below instead.
 extern const char kChildAccountStatusKnown[];
 extern const char kDefaultApps[];
 extern const char kDisableScreenshots[];
 extern const char kForceEphemeralProfiles[];
 extern const char kHomePageIsNewTabPage[];
 extern const char kHomePage[];
 #if defined(OS_WIN)
 extern const char kLastProfileResetTimestamp[];
 #endif
 extern const char kProfileIconVersion[];
 extern const char kRestoreOnStartup[];
-extern const char kRestoreOnStartupMigrated[];
 extern const char kSessionExitedCleanly[];
 extern const char kSessionExitType[];
 extern const char kSupervisedUserCustodianEmail[];
 extern const char kSupervisedUserCustodianName[];
 extern const char kSupervisedUserCustodianProfileImageURL[];
 extern const char kSupervisedUserCustodianProfileURL[];
 extern const char kSupervisedUserManualHosts[];
 extern const char kSupervisedUserManualURLs[];
 extern const char kSupervisedUserSafeSites[];
 extern const char kSupervisedUserSecondCustodianEmail[];
@@ skipping 747 matching lines @@
 extern const char kAnimationPolicy[];
 #endif
 
 extern const char kBackgroundTracingLastUpload[];
 
 extern const char kAllowDinosaurEasterEgg[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_