diff --git a/delta_performer.h b/delta_performer.h
index 403ab8f..a95e4e1 100644
--- a/delta_performer.h
+++ b/delta_performer.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__
-#define CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H_
 
 #include <inttypes.h>
 
@@ -361,4 +361,4 @@
 
 }  // namespace chromeos_update_engine
 
-#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H_