diff --git a/test_utils.cc b/test_utils.cc
index b452ca3..70eb35c 100644
--- a/test_utils.cc
+++ b/test_utils.cc
@@ -319,7 +319,7 @@
 }
 
 void RunGMainLoopUntil(int timeout_msec, base::Callback<bool()> terminate) {
-  GMainLoop* loop = g_main_loop_new(NULL, FALSE);
+  GMainLoop* loop = g_main_loop_new(nullptr, FALSE);
   GMainContext* context = g_main_context_default();
 
   bool timeout = false;