sync: Introduce control data types

sync/engine/apply_control_data_updates.h

Index: sync/engine/apply_control_data_updates.h
diff --git a/sync/engine/apply_control_data_updates.h b/sync/engine/apply_control_data_updates.h
new file mode 100644
index 0000000000000000000000000000000000000000..efe2cc8f23118396c45da114d5223d0735a66d38
--- /dev/null
+++ b/sync/engine/apply_control_data_updates.h
@@ -0,0 +1,23 @@
+// 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.
+
+#ifndef SYNC_ENGINE_APPLY_CONTROL_DATA_UPDATES_H_
+#define SYNC_ENGINE_APPLY_CONTROL_DATA_UPDATES_H_
+
+namespace syncer {
+
+class Cryptographer;
+
+namespace syncable {
+class Directory;
+class WriteTransaction;
+}
+
+void ApplyControlDataUpdates(syncable::Directory* dir);
+bool ApplyNigoriUpdates(syncable::WriteTransaction* trans,
+                        Cryptographer* cryptographer);
+
+}  // namespace syncer
+
+#endif  // SYNC_ENGINE_APPLY_CONTROL_DATA_UPDATES_H_