Use update_engine_service_new() from main().

This a simple fix that uses the update_engine_service_new() function
to create an UpdateEngineService.

BUG=None
TEST=gmerge on the device; restart update-engine; tested the DBus interface works with:
dbus-send --system --dest=org.chromium.UpdateEngine --print-reply /org/chromium/UpdateEngine org.chromium.UpdateEngineInterface.GetStatus

Change-Id: I862007d9bb6cb0dff5c8e3f35580b6471758be40
Reviewed-on: https://chromium-review.googlesource.com/197852
Reviewed-by: Chris Sosa <sosa@chromium.org>
Tested-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
diff --git a/main.cc b/main.cc
index cc05099..9d2a869 100644
--- a/main.cc
+++ b/main.cc
@@ -193,8 +193,7 @@
   // Create the dbus service object:
   dbus_g_object_type_install_info(UPDATE_ENGINE_TYPE_SERVICE,
                                   &dbus_glib_update_engine_service_object_info);
-  UpdateEngineService* service =
-      UPDATE_ENGINE_SERVICE(g_object_new(UPDATE_ENGINE_TYPE_SERVICE, nullptr));
+  UpdateEngineService* service = update_engine_service_new();
   service->system_state_ = &real_system_state;
   update_attempter->set_dbus_service(service);
   chromeos_update_engine::SetupDbusService(service);