[Sync] Move //components/sync_driver to //components/sync/driver.

components/sync_driver/device_info_tracker.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_SYNC_DRIVER_DEVICE_INFO_TRACKER_H_
-#define COMPONENTS_SYNC_DRIVER_DEVICE_INFO_TRACKER_H_
-
-#include <memory>
-#include <string>
-
-#include "base/memory/scoped_vector.h"
-#include "components/sync_driver/device_info.h"
-
-namespace sync_driver {
-
-// Interface for tracking synced DeviceInfo.
-class DeviceInfoTracker {
- public:
-  virtual ~DeviceInfoTracker() {}
-
-  // Observer class for listening to device info changes.
-  class Observer {
-   public:
-    virtual void OnDeviceInfoChange() = 0;
-  };
-
-  // Returns true when DeviceInfo datatype is enabled and syncing.
-  virtual bool IsSyncing() const = 0;
-  // Gets DeviceInfo the synced device with specified client ID.
-  // Returns an empty unique_ptr if device with the given |client_id| hasn't
-  // been synced.
-  virtual std::unique_ptr<DeviceInfo> GetDeviceInfo(
-      const std::string& client_id) const = 0;
-  // Gets DeviceInfo for all synced devices (including the local one).
-  virtual ScopedVector<DeviceInfo> GetAllDeviceInfo() const = 0;
-  // Registers an observer to be called on syncing any updated DeviceInfo.
-  virtual void AddObserver(Observer* observer) = 0;
-  // Unregisters an observer.
-  virtual void RemoveObserver(Observer* observer) = 0;
-  // Returns the count of active devices.
-  virtual int CountActiveDevices() const = 0;
-};
-
-}  // namespace sync_driver
-
-#endif  // COMPONENTS_SYNC_DRIVER_DEVICE_INFO_TRACKER_H_