components: Cleanup class/struct fwd declarations

components/sync/driver/sync_api_component_factory.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_SYNC_API_COMPONENT_FACTORY_H_
 #define COMPONENTS_SYNC_DRIVER_SYNC_API_COMPONENT_FACTORY_H_
 
 #include <memory>
 #include <string>
 
 #include "base/memory/weak_ptr.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/driver/data_type_controller.h"
 #include "components/sync/model/attachments/attachment_service.h"
 #include "components/sync/model/data_type_error_handler.h"
 #include "components/sync/model/syncable_service.h"
 
 namespace base {
 class FilePath;
 }  // namespace base
 
-namespace history {
-class HistoryBackend;
-}
-
 namespace invalidation {
 class InvalidationService;
 }  // namespace invalidation
 
 namespace syncer {
 
 class AssociatorInterface;
 class ChangeProcessor;
 class DataTypeDebugInfoListener;
 class DataTypeEncryptionHandler;
 class DataTypeManager;
 class DataTypeManagerObserver;
-class DataTypeStatusTable;
-class GenericChangeProcessor;
 class LocalDeviceInfoProvider;
 class SyncBackendHost;
 class SyncClient;
 class SyncPrefs;
 class SyncService;
 class SyncableService;
 struct UserShare;
 
 // This factory provides sync driver code with the model type specific sync/api
 // service (like SyncableService) implementations.
@@ skipping 75 matching lines @@
       std::unique_ptr<AttachmentStoreForSync> attachment_store,
       const UserShare& user_share,
       const std::string& store_birthday,
       ModelType model_type,
       AttachmentService::Delegate* delegate) = 0;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_SYNC_API_COMPONENT_FACTORY_H_