ifdef OS_NAME -> if defined(OS_NAME)

chrome/browser/ui/webui/flags_ui.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_FLAGS_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_FLAGS_UI_H_
 
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/web_ui_controller.h"
 #include "ui/base/layout.h"
 
-#ifdef OS_CHROMEOS
+#if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/settings/device_settings_service.h"
 #endif
 
 class PrefRegistrySimple;
 class PrefRegistrySyncable;
 class Profile;
 
 namespace base {
 class RefCountedMemory;
 }
 
 class FlagsUI : public content::WebUIController {
  public:
   explicit FlagsUI(content::WebUI* web_ui);
   virtual ~FlagsUI();
 
   static base::RefCountedMemory* GetFaviconResourceBytes(
       ui::ScaleFactor scale_factor);
   static void RegisterPrefs(PrefRegistrySimple* registry);
-#ifdef OS_CHROMEOS
+#if defined(OS_CHROMEOS)
   static void RegisterUserPrefs(PrefRegistrySyncable* registry);
 #endif
 
  private:
-#ifdef OS_CHROMEOS
+#if defined(OS_CHROMEOS)
   // On ChromeOS verifying if the owner is signed in is async operation and only
   // after finishing it the UI can be properly populated. This function is the
   // callback for whether the owner is signed in. It will respectively pick the
   // proper PrefService for the flags interface.
   void FinishInitialization(
       Profile* profile,
       chromeos::DeviceSettingsService::OwnershipStatus status,
       bool current_user_is_owner);
 #endif
   base::WeakPtrFactory<FlagsUI> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FlagsUI);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_FLAGS_UI_H_