diff --git a/action_processor.h b/action_processor.h
index 696afd4..32457a8 100644
--- a/action_processor.h
+++ b/action_processor.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_ACTION_PROCESSOR_H__
-#define CHROMEOS_PLATFORM_UPDATE_ENGINE_ACTION_PROCESSOR_H__
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_ACTION_PROCESSOR_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_ACTION_PROCESSOR_H_
 
 #include <deque>
 
@@ -99,4 +99,4 @@
 
 }  // namespace chromeos_update_engine
 
-#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_ACTION_PROCESSOR_H__
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_ACTION_PROCESSOR_H_