sync: Add DeviceInfo protobuf and supporting code

chrome/browser/sync/glue/device_info.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.
+
+#ifndef CHROME_BROWSER_SYNC_GLUE_DEVICE_INFO_H_
+#define CHROME_BROWSER_SYNC_GLUE_DEVICE_INFO_H_
+
+#include <string>
+
+#include "base/bind.h"
+#include "sync/protocol/sync.pb.h"
+
+namespace chrome {
+class VersionInfo;
+}
+
+namespace browser_sync {
+
+// A class that holds information regarding the properties of a device.
+//
+// These objects do not contain enough information to uniquely identify devices.
+// Two different devices may end up generating identical DeviceInfos.
+class DeviceInfo {
+ public:
+  DeviceInfo();
+  DeviceInfo(const std::string& client_name,
+             const std::string& chrome_version,
+             const std::string& sync_user_agent,
+             const sync_pb::SyncEnums::DeviceType device_type);
+  ~DeviceInfo();
+
+  const std::string& client_name() const;
+  const std::string& chrome_version() const;
+  const std::string& sync_user_agent() const;
+  sync_pb::SyncEnums::DeviceType device_type() const;
+
+  // Compares this object's fields with another's.
+  bool Equals(const DeviceInfo& other) const;
+
+  static sync_pb::SyncEnums::DeviceType GetLocalDeviceType();
+  static void CreateLocalDeviceInfo(
+      base::Callback<void(const DeviceInfo& local_info)> callback);
+
+  // Helper to construct a user agent string (ASCII) suitable for use by
+  // the syncapi for any HTTP communication. This string is used by the sync
+  // backend for classifying client types when calculating statistics.
+  static std::string MakeUserAgentForSyncApi(
+      const chrome::VersionInfo& version_info);
+
+ private:
+  static void CreateLocalDeviceInfoContinuation(
+      base::Callback<void(const DeviceInfo& local_info)> callback,
+      const std::string& session_name);
+
+  const std::string client_name_;
+  const std::string chrome_version_;
+  const std::string sync_user_agent_;
+  const sync_pb::SyncEnums::DeviceType device_type_;
+};
+
+}
+
+#endif  // CHROME_BROWSER_SYNC_GLUE_DEVICE_INFO_H_