Let SyncBackupManager keep backup data in memory until shutdown. Only persist

chrome/browser/sync/test_profile_sync_service.cc

Index: chrome/browser/sync/test_profile_sync_service.cc
diff --git a/chrome/browser/sync/test_profile_sync_service.cc b/chrome/browser/sync/test_profile_sync_service.cc
index 6242dd9433fe401c2b67171a0da496f6dc995794..13982d2bdc4985f9fc3a90e06afcd71cf339f0b8 100644
--- a/chrome/browser/sync/test_profile_sync_service.cc
+++ b/chrome/browser/sync/test_profile_sync_service.cc
@@ -61,8 +61,9 @@ void SyncBackendHostForProfileSyncTest::InitCore(
   InternalComponentsFactory::Switches factory_switches =
       options->internal_components_factory->GetSwitches();
   options->internal_components_factory.reset(
-      new TestInternalComponentsFactory(factory_switches,
-                                        syncer::STORAGE_IN_MEMORY));
+      new TestInternalComponentsFactory(
+          factory_switches, InternalComponentsFactory::STORAGE_IN_MEMORY,
+          InternalComponentsFactory::STORAGE_ON_DISK));
 
   SyncBackendHostImpl::InitCore(options.Pass());
 }