[Sync] Add SyncEncryptionHandler

sync/syncable/nigori_util.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.
 
 // Various utility methods for nigori-based multi-type encryption.
 
 #ifndef SYNC_SYNCABLE_NIGORI_UTIL_H_
 #define SYNC_SYNCABLE_NIGORI_UTIL_H_
 
 #include "base/compiler_specific.h"
@@ skipping 50 matching lines @@
     bool is_encrypted) WARN_UNUSED_RESULT;
 
 // Stores |new_specifics| into |entry|, encrypting if necessary.
 // Returns false if an error encrypting occurred (does not modify |entry|).
 // Note: gracefully handles new_specifics aliasing with entry->Get(SPECIFICS).
 bool UpdateEntryWithEncryption(
     Cryptographer* cryptographer,
     const sync_pb::EntitySpecifics& new_specifics,
     MutableEntry* entry);
 
+// Updates |nigori| to match the encryption state specified by |encrypted_types|
+// and |encrypt_everything|.
+void UpdateNigoriFromEncryptedTypes(ModelTypeSet encrypted_types,
+                                    bool encrypt_everything,
+                                    sync_pb::NigoriSpecifics* nigori);
+
 }  // namespace syncable
 }  // namespace syncer
 
 #endif  // SYNC_SYNCABLE_NIGORI_UTIL_H_