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

components/sync_driver/sync_service_observer.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 COMPONENTS_SYNC_DRIVER_SYNC_SERVICE_OBSERVER_H_
-#define COMPONENTS_SYNC_DRIVER_SYNC_SERVICE_OBSERVER_H_
-
-namespace sync_driver {
-
-// Various UI components such as the New Tab page can be driven by observing
-// the SyncService through this interface.
-class SyncServiceObserver {
- public:
-  // When one of the following events occurs, OnStateChanged() is called.
-  // Observers should query the service to determine what happened.
-  // - We initialized successfully.
-  // - The sync servers are unavailable at this time.
-  // - Credentials are now in flight for authentication.
-  // - The data type configuration has started or ended.
-  // - Sync shut down.
-  // - Sync errors (passphrase, auth, unrecoverable, actionable, etc.).
-  // - Encryption changes.
-  virtual void OnStateChanged() = 0;
-
-  // If a client wishes to handle sync cycle completed events in a special way,
-  // they can use this function.  By default, it re-routes to OnStateChanged().
-  virtual void OnSyncCycleCompleted();
-
-  // Called when the sync service has finished the datatype configuration
-  // process.
-  virtual void OnSyncConfigurationCompleted() {}
-
-  // Called when a foreign session has been updated.
-  virtual void OnForeignSessionUpdated() {}
-
- protected:
-  virtual ~SyncServiceObserver() {}
-};
-
-}  // namespace sync_driver
-
-#endif  // COMPONENTS_SYNC_DRIVER_SYNC_SERVICE_OBSERVER_H_