Move enable extensions define to a build flag.

chrome/browser/download/download_service.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_DOWNLOAD_DOWNLOAD_SERVICE_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_SERVICE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/keyed_service/core/keyed_service.h"
+#include "extensions/features/features.h"
 
 class ChromeDownloadManagerDelegate;
 class DownloadHistory;
 class ExtensionDownloadsEventRouter;
 class Profile;
 
 namespace content {
 class DownloadManager;
 }
 
 namespace extensions {
 class ExtensionDownloadsEventRouter;
 }
 
 // Abstract base class for the download service; see DownloadServiceImpl for
 // implementation.
 class DownloadService : public KeyedService {
  public:
   DownloadService();
   ~DownloadService() override;
 
   // Get the download manager delegate, creating it if it doesn't already exist.
   virtual ChromeDownloadManagerDelegate* GetDownloadManagerDelegate() = 0;
 
   // Get the interface to the history system. Returns NULL if profile is
   // incognito or if the DownloadManager hasn't been created yet or if there is
   // no HistoryService for profile. Virtual for testing.
   virtual DownloadHistory* GetDownloadHistory() = 0;
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   virtual extensions::ExtensionDownloadsEventRouter*
   GetExtensionEventRouter() = 0;
 #endif
 
   // Has a download manager been created?
   virtual bool HasCreatedDownloadManager() = 0;
 
   // Number of non-malicious downloads associated with this instance of the
   // service.
   virtual int NonMaliciousDownloadCount() const = 0;
@@ skipping 15 matching lines @@
 
   // Returns false if at least one extension has disabled the shelf, true
   // otherwise.
   virtual bool IsShelfEnabled() = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DownloadService);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_SERVICE_H_