Move enable extensions define to a build flag.

chrome/browser/autocomplete/shortcuts_extensions_manager.cc

 // Copyright 2015 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.
 
 #include "chrome/browser/autocomplete/shortcuts_extensions_manager.h"
 
 #include "chrome/browser/autocomplete/shortcuts_backend_factory.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/omnibox/browser/shortcuts_backend.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
+#include "extensions/features/features.h"
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 #include "extensions/browser/notification_types.h"
 #include "extensions/common/extension.h"
 #endif
 
 ShortcutsExtensionsManager::ShortcutsExtensionsManager(Profile* profile)
     : profile_(profile) {
   DCHECK(profile_);
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   notification_registrar_.Add(
       this, extensions::NOTIFICATION_EXTENSION_UNLOADED_DEPRECATED,
       content::Source<Profile>(profile_));
 #endif
 }
 
 ShortcutsExtensionsManager::~ShortcutsExtensionsManager() {}
 
 void ShortcutsExtensionsManager::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   DCHECK_EQ(extensions::NOTIFICATION_EXTENSION_UNLOADED_DEPRECATED, type);
   scoped_refptr<ShortcutsBackend> shortcuts_backend =
       ShortcutsBackendFactory::GetForProfileIfExists(profile_);
   if (!shortcuts_backend)
     return;
 
   // When an extension is unloaded, we want to remove any Shortcuts associated
   // with it.
   shortcuts_backend->DeleteShortcutsBeginningWithURL(
       content::Details<extensions::UnloadedExtensionInfo>(details)
           ->extension->url());
 #endif
 }