Extract protobuf database into a new 'leveldb_proto' component

components/leveldb_proto/leveldb_database.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 COMPONENTS_LEVELDB_PROTO_LEVELDB_DATABASE_H_
+#define COMPONENTS_LEVELDB_PROTO_LEVELDB_DATABASE_H_
+
+#include <string>
+#include <vector>
+
+#include "base/files/file_path.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/thread_collision_warner.h"
+
+namespace leveldb {
+class DB;
+}  // namespace leveldb
+
+namespace leveldb_proto {
+
+// Interacts with the LevelDB third party module.
+// Once constructed, function calls and destruction should all occur on the
+// same thread (not necessarily the same as the constructor).
+class LevelDB {
+ public:
+  LevelDB();
+  virtual ~LevelDB();
+
+  virtual bool Init(const base::FilePath& database_dir);
+  virtual bool Save(
+      const std::vector<std::pair<std::string, std::string> >& pairs_to_save,
+      const std::vector<std::string>& keys_to_remove);
+  virtual bool Load(std::vector<std::string>* entries);
+
+ private:
+  DFAKE_MUTEX(thread_checker_);
+  scoped_ptr<leveldb::DB> db_;
+};
+
+}  // namespace leveldb_proto
+
+#endif  // COMPONENTS_LEVELDB_PROTO_LEVELDB_DATABASE_H_