[Sync] Convert DTCs to be not RefCounted and NonThreadSafe.

components/sync/driver/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/change_processor.h"
 
+#include <utility>
+
 namespace sync_driver {
 
-ChangeProcessor::ChangeProcessor(syncer::DataTypeErrorHandler* error_handler)
-    : error_handler_(error_handler), share_handle_(NULL) {}
+ChangeProcessor::ChangeProcessor(
+    std::unique_ptr<syncer::DataTypeErrorHandler> error_handler)
+    : error_handler_(std::move(error_handler)), share_handle_(NULL) {}
 
 ChangeProcessor::~ChangeProcessor() {}
 
 void ChangeProcessor::Start(syncer::UserShare* share_handle) {
   DCHECK(!share_handle_);
   share_handle_ = share_handle;
   StartImpl();
 }
 
 // Not implemented by default.
 void ChangeProcessor::CommitChangesFromSyncModel() {}
 
 syncer::DataTypeErrorHandler* ChangeProcessor::error_handler() const {
-  return error_handler_;
+  return error_handler_.get();
 }
 
 syncer::UserShare* ChangeProcessor::share_handle() const {
   return share_handle_;
 }
 
 }  // namespace sync_driver