[Sync] Removing duplicated includes between cc and h files.

components/sync/driver/generic_change_processor.cc

 // 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.
 
 #include "components/sync/driver/generic_change_processor.h"
 
 #include <stddef.h>
 
 #include <algorithm>
-#include <string>
 #include <utility>
 
 #include "base/location.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
-#include "components/sync/api/data_type_error_handler.h"
 #include "components/sync/api/local_change_observer.h"
 #include "components/sync/api/sync_change.h"
 #include "components/sync/api/sync_error.h"
 #include "components/sync/api/syncable_service.h"
 #include "components/sync/base/unrecoverable_error_handler.h"
 #include "components/sync/core/base_node.h"
 #include "components/sync/core/change_record.h"
 #include "components/sync/core/read_node.h"
 #include "components/sync/core/read_transaction.h"
 #include "components/sync/core/write_node.h"
@@ skipping 679 matching lines @@
                     OnLocalChange(current_entry, change));
 }
 
 std::unique_ptr<syncer::AttachmentService>
 GenericChangeProcessor::GetAttachmentService() const {
   return std::unique_ptr<syncer::AttachmentService>(
       new syncer::AttachmentServiceProxy(attachment_service_proxy_));
 }
 
 }  // namespace sync_driver