[Sync] Don't synchronously stop datatypes that encounter errors

components/sync_driver/ui_data_type_controller.cc

Index: components/sync_driver/ui_data_type_controller.cc
diff --git a/components/sync_driver/ui_data_type_controller.cc b/components/sync_driver/ui_data_type_controller.cc
index eca577920b85cbf995ca7861991ada92f58f8691..23487a2edb8e415c81752e4409b55c95cfc80122 100644
--- a/components/sync_driver/ui_data_type_controller.cc
+++ b/components/sync_driver/ui_data_type_controller.cc
@@ -331,9 +331,12 @@ void UIDataTypeController::OnSingleDataTypeUnrecoverableError(
   if (!start_callback_.is_null()) {
     syncer::SyncMergeResult local_merge_result(type());
     local_merge_result.set_error(error);
-    start_callback_.Run(RUNTIME_ERROR,
-                        local_merge_result,
-                        syncer::SyncMergeResult(type()));
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(start_callback_,
+                   RUNTIME_ERROR,
+                   local_merge_result,
+                   syncer::SyncMergeResult(type())));
   }
 }