diff --git a/install_plan.h b/install_plan.h
index 29ce212..9090f0b 100644
--- a/install_plan.h
+++ b/install_plan.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_INSTALL_PLAN_H__
-#define CHROMEOS_PLATFORM_UPDATE_ENGINE_INSTALL_PLAN_H__
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_INSTALL_PLAN_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_INSTALL_PLAN_H_
 
 #include <string>
 #include <vector>
@@ -121,4 +121,4 @@
 
 }  // namespace chromeos_update_engine
 
-#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_INSTALL_PLAN_H__
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_INSTALL_PLAN_H_