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

sync/engine/sync_engine_event_listener.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 SYNC_ENGINE_SYNC_ENGINE_EVENT_LISTENER_H_
-#define SYNC_ENGINE_SYNC_ENGINE_EVENT_LISTENER_H_
-
-#include "base/time/time.h"
-#include "sync/base/sync_export.h"
-#include "sync/internal_api/public/base/model_type.h"
-
-namespace syncer {
-
-struct SyncProtocolError;
-struct SyncCycleEvent;
-class ProtocolEvent;
-
-class SYNC_EXPORT SyncEngineEventListener {
- public:
-  SyncEngineEventListener();
-
-  // Generated at various points during the sync cycle.
-  virtual void OnSyncCycleEvent(const SyncCycleEvent& event) = 0;
-
-  // This event is sent when we receive an actionable error. It is up to
-  // the listeners to figure out the action to take using the error sent.
-  virtual void OnActionableError(const SyncProtocolError& error) = 0;
-
-  // This event is sent when scheduler decides to wait before next request
-  // either because it gets throttled by server or because it backs off after
-  // request failure. Retry time is passed in retry_time field of event.
-  virtual void OnRetryTimeChanged(base::Time retry_time) = 0;
-
-  // This event is sent when types are throttled or unthrottled.
-  virtual void OnThrottledTypesChanged(ModelTypeSet throttled_types) = 0;
-
-  // This event is sent when the server requests a migration.
-  virtual void OnMigrationRequested(ModelTypeSet migration_types) = 0;
-
-  // Emits events when sync communicates with the server.
-  virtual void OnProtocolEvent(const ProtocolEvent& event) = 0;
-
- protected:
-  virtual ~SyncEngineEventListener();
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_ENGINE_SYNC_ENGINE_EVENT_LISTENER_H_