cros: Mount the existing eCryptfs vault to start migration.

chromeos/cryptohome/cryptohome_parameters.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_CRYPTOHOME_CRYPTOHOME_PARAMETERS_H_
 #define CHROMEOS_CRYPTOHOME_CRYPTOHOME_PARAMETERS_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 152 matching lines @@
   // used as the backend.
   bool ephemeral;
 
   // If not empty, home dir will be created with these keys if it exist.
   std::vector<KeyDefinition> create_keys;
 
   // If |true|, and cryptohomed supports the new "dircrypto" encryption,
   // forces to use the new encryption. That is, makes it an error to mount
   // an existing home directory encrypted in the old way (ecryptfs).
   bool force_dircrypto_if_available = false;
+
+  // If |true|, mounts the existing ecryptfs vault to a temporary location while
+  // setting up a new dircrypto directory.
+  bool to_migrate_from_ecryptfs = false;
 };
 
 // This function returns true if cryptohome of |account_id| is migrated to
 // accountId-based identifier (AccountId::GetAccountIdKey()).
 bool GetGaiaIdMigrationStatus(const AccountId& account_id);
 
 // This function marks |account_id| cryptohome migrated to accountId-based
 // identifier (AccountId::GetAccountIdKey()).
 void SetGaiaIdMigrationStatusDone(const AccountId& account_id);
 
 }  // namespace cryptohome
 
 namespace BASE_HASH_NAMESPACE {
 
 // Implement hashing of cryptohome::Identification, so it can be used as a key
 // in STL containers.
 template <>
 struct hash<cryptohome::Identification> {
   std::size_t operator()(const cryptohome::Identification& cryptohome_id) const;
 };
 
 }  // namespace BASE_HASH_NAMESPACE
 
 #endif  // CHROMEOS_CRYPTOHOME_CRYPTOHOME_PARAMETERS_H_