Move enable extensions define to a build flag.

chrome/browser/browser_process_impl.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.
 
 // When each service is created, we set a flag indicating this. At this point,
 // the service initialization could fail or succeed. This allows us to remember
 // if we tried to create a service, and not try creating it over and over if
 // the creation failed.
 
 #ifndef CHROME_BROWSER_BROWSER_PROCESS_IMPL_H_
 #define CHROME_BROWSER_BROWSER_PROCESS_IMPL_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 
 #include "base/debug/stack_trace.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/lifetime/keep_alive_state_observer.h"
 #include "chrome/common/features.h"
 #include "components/prefs/pref_change_registrar.h"
+#include "extensions/features/features.h"
 #include "printing/features/features.h"
 
 class ChromeChildProcessWatcher;
 class ChromeDeviceClient;
 class ChromeResourceDispatcherHostDelegate;
 class DevToolsAutoOpener;
 class RemoteDebuggingServer;
 class PrefRegistrySimple;
 
 #if BUILDFLAG(ENABLE_PLUGIN_INSTALLATION)
@@ skipping 173 matching lines @@
   bool created_local_state_;
   std::unique_ptr<PrefService> local_state_;
 
   bool created_icon_manager_;
   std::unique_ptr<IconManager> icon_manager_;
 
   std::unique_ptr<GpuProfileCache> gpu_profile_cache_;
 
   std::unique_ptr<GpuModeManager> gpu_mode_manager_;
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   std::unique_ptr<extensions::ExtensionsBrowserClient>
       extensions_browser_client_;
 
   scoped_refptr<extensions::EventRouterForwarder>
       extension_event_router_forwarder_;
 
   std::unique_ptr<MediaFileSystemRegistry> media_file_system_registry_;
 #endif
 
 #if !defined(OS_ANDROID)
@@ skipping 114 matching lines @@
 #endif
 
   shell_integration::DefaultWebClientState cached_default_web_client_state_;
 
   std::unique_ptr<PhysicalWebDataSource> physical_web_data_source_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserProcessImpl);
 };
 
 #endif  // CHROME_BROWSER_BROWSER_PROCESS_IMPL_H_