[Sync] Add SyncEncryptionHandler

sync/syncable/nigori_handler.h

Index: sync/syncable/nigori_handler.h
diff --git a/sync/syncable/nigori_handler.h b/sync/syncable/nigori_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..94bb6449aeef981092adf4b0b95ef03bc3863c7a
--- /dev/null
+++ b/sync/syncable/nigori_handler.h
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+// 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_SYNCABLE_NIGORI_HANDLER_H_
+#define SYNC_SYNCABLE_NIGORI_HANDLER_H_
+
+#include "sync/internal_api/public/base/model_type.h"
+
+namespace sync_pb {
+class NigoriSpecifics;
+}
+
+namespace syncer {
+namespace syncable {
+
+class BaseTransaction;
+
+// Sync internal interface for dealing with nigori node and querying
+// the current set of encrypted types. Not thread safe, so a sync transaction
+// must be held by a caller whenever invoking methods.
+class NigoriHandler {
+ public:
+  NigoriHandler();
+  virtual ~NigoriHandler();
+
+  // Apply a nigori node update, updating the internal encryption state
+  // accordingly.
+  virtual void ApplyNigoriUpdate(
+      const sync_pb::NigoriSpecifics& nigori,
+      syncable::BaseTransaction* const trans) = 0;
+
+  // Store the current encrypt everything/encrypted types state into |nigori|.
+  virtual void UpdateNigoriFromEncryptedTypes(
+      sync_pb::NigoriSpecifics* nigori,
+      syncable::BaseTransaction* const trans) const = 0;
+
+  // Returns the set of currently encrypted types.
+  // TODO(zea): force callers to pass their syncable trans here.
+  virtual ModelTypeSet GetEncryptedTypes() const = 0;
+};
+
+}  // namespace syncable
+}  // namespace syncer
+
+#endif  // SYNC_SYNCABLE_NIGORI_HANDLER_H_