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

components/browser_sync/profile_sync_test_util.cc

Index: components/browser_sync/profile_sync_test_util.cc
diff --git a/components/browser_sync/profile_sync_test_util.cc b/components/browser_sync/profile_sync_test_util.cc
index 90cdff69f079dd39cb3a7098dc8960d69489d63b..ee186d14d3c41cfdd6ee09c2463b6fcb3637eacd 100644
--- a/components/browser_sync/profile_sync_test_util.cc
+++ b/components/browser_sync/profile_sync_test_util.cc
@@ -19,8 +19,6 @@
 #include "components/sync/engine/passive_model_worker.h"
 #include "components/sync/engine/ui_model_worker.h"
 #include "net/url_request/url_request_test_util.h"
-
-using ServiceProvider = syncer::SyncClient::ServiceProvider;
 
 namespace browser_sync {
 
@@ -47,7 +45,8 @@
   PrefService* GetPrefService() override;
   sync_sessions::SyncSessionsClient* GetSyncSessionsClient() override;
   autofill::PersonalDataManager* GetPersonalDataManager() override;
-  ServiceProvider GetSyncableServiceForType(syncer::ModelType type) override;
+  base::WeakPtr<syncer::SyncableService> GetSyncableServiceForType(
+      syncer::ModelType type) override;
   syncer::SyncService* GetSyncService() override;
   scoped_refptr<syncer::ModelSafeWorker> CreateModelWorkerForGroup(
       syncer::ModelSafeGroup group) override;
@@ -110,11 +109,11 @@
   return personal_data_manager_;
 }
 
-ServiceProvider BundleSyncClient::GetSyncableServiceForType(
-    syncer::ModelType type) {
+base::WeakPtr<syncer::SyncableService>
+BundleSyncClient::GetSyncableServiceForType(syncer::ModelType type) {
   if (get_syncable_service_callback_.is_null())
     return syncer::FakeSyncClient::GetSyncableServiceForType(type);
-  return base::Bind(get_syncable_service_callback_, type);
+  return get_syncable_service_callback_.Run(type);
 }
 
 syncer::SyncService* BundleSyncClient::GetSyncService() {