Force encryption migration if the device supports ARC.

chrome/browser/flag_descriptions.h

 // Copyright 2017 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.
 
 #ifndef CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 #define CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 
 // Includes needed for macros allowing conditional compilation of some strings.
 #include "build/build_config.h"
 #include "build/buildflag.h"
@@ skipping 3142 matching lines @@
 extern const char kEnableImeMenuDescription[];
 
 // Name of the about: flag for enabling emoji, handwriting and voice input on
 // opt-in IME menu.
 extern const char kEnableEhvInputName[];
 
 // Description of the about: flag enabling emoji, handwriting and voice input on
 // opt-in IME menu.
 extern const char kEnableEhvInputDescription[];
 
+// Name of the about: flag for enabling encryption migratoin, which ensures the
+// user's cryptohome is encrypted by ext4 dircrypto instead of ecryptfs.
+extern const char kEnableEncryptionMigrationName[];
+
+// Description of the about: flag for enabling encryption migratoin.
+extern const char kEnableEncryptionMigrationDescription[];
+
 #endif  // #if defined(OS_CHROMEOS)
 
 }  // namespace flag_descriptions
 
 #endif  // CHROME_BROWSER_FLAG_DESCRIPTIONS_H_