Implement a basic UI flow for cryptohome encryption migration.

chromeos/login/auth/auth_status_consumer.h

 // Copyright 2014 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 CHROMEOS_LOGIN_AUTH_AUTH_STATUS_CONSUMER_H_
 #define CHROMEOS_LOGIN_AUTH_AUTH_STATUS_CONSUMER_H_
 
 #include <string>
 
 #include "base/logging.h"
@@ skipping 103 matching lines @@
   // The current login attempt has ended in failure, with error |error|.
   virtual void OnAuthFailure(const AuthFailure& error) = 0;
 
   // The current login attempt has succeeded for |user_context|.
   virtual void OnAuthSuccess(const UserContext& user_context) = 0;
   // The current guest login attempt has succeeded.
   virtual void OnOffTheRecordAuthSuccess() {}
   // The same password didn't work both online and offline.
   virtual void OnPasswordChangeDetected();
   // The cryptohome is encrypted in old format and needs migration.
-  virtual void OnOldEncryptionDetected();
+  virtual void OnOldEncryptionDetected(const UserContext& user_context);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_LOGIN_AUTH_AUTH_STATUS_CONSUMER_H_