[Sync] Stop accessing BrowserContextKeyedServiceFactory on non-UI thread.

components/sync/driver/directory_data_type_controller.cc

 // Copyright (c) 2015 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/directory_data_type_controller.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/memory/ptr_util.h"
@@ skipping 44 matching lines @@
 
 void DirectoryDataTypeController::DeactivateDataType(
     ModelTypeConfigurer* configurer) {
   DCHECK(CalledOnValidThread());
   configurer->DeactivateDirectoryDataType(type());
   configurer->UnregisterDirectoryDataType(type());
 }
 
 void DirectoryDataTypeController::GetAllNodes(
     const AllNodesCallback& callback) {
+  DCHECK(CalledOnValidThread());
   std::unique_ptr<base::ListValue> node_list = GetAllNodesForTypeFromDirectory(
       type(), sync_client_->GetSyncService()->GetUserShare()->directory.get());
   callback.Run(type(), std::move(node_list));
 }
 
 void DirectoryDataTypeController::GetStatusCounters(
     const StatusCountersCallback& callback) {
+  DCHECK(CalledOnValidThread());
   std::vector<int> num_entries_by_type(syncer::MODEL_TYPE_COUNT, 0);
   std::vector<int> num_to_delete_entries_by_type(syncer::MODEL_TYPE_COUNT, 0);
   sync_client_->GetSyncService()
       ->GetUserShare()
       ->directory->CollectMetaHandleCounts(&num_entries_by_type,
                                            &num_to_delete_entries_by_type);
   syncer::StatusCounters counters;
   counters.num_entries_and_tombstones = num_entries_by_type[type()];
   counters.num_entries =
       num_entries_by_type[type()] - num_to_delete_entries_by_type[type()];
 
   callback.Run(type(), counters);
 }
 
 // static
 std::unique_ptr<base::ListValue>
 DirectoryDataTypeController::GetAllNodesForTypeFromDirectory(
     ModelType type,
     syncable::Directory* directory) {
   DCHECK(directory);
   syncable::ReadTransaction trans(FROM_HERE, directory);
   return directory->GetNodeDetailsForType(&trans, type);
 }
 
 }  // namespace syncer