Move enable extensions define to a build flag.

chrome/browser/loader/chrome_resource_dispatcher_host_delegate.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_LOADER_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_
 #define CHROME_BROWSER_LOADER_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_
 
 #include <map>
 #include <memory>
 #include <set>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/external_protocol/external_protocol_handler.h"
 #include "content/public/browser/resource_dispatcher_host_delegate.h"
+#include "extensions/features/features.h"
 
 class DelayedResourceQueue;
 class DownloadRequestLimiter;
 
 namespace content {
 class NavigationData;
 }
 
 namespace extensions {
 class UserScriptListener;
@@ skipping 72 matching lines @@
 
  protected:
   // Virtual for testing.
   virtual void AppendStandardResourceThrottles(
       net::URLRequest* request,
       content::ResourceContext* resource_context,
       content::ResourceType resource_type,
       ScopedVector<content::ResourceThrottle>* throttles);
 
  private:
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   struct StreamTargetInfo {
     std::string extension_id;
     std::string view_id;
   };
 #endif
 
   scoped_refptr<DownloadRequestLimiter> download_request_limiter_;
   scoped_refptr<safe_browsing::SafeBrowsingService> safe_browsing_;
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   scoped_refptr<extensions::UserScriptListener> user_script_listener_;
   std::map<net::URLRequest*, StreamTargetInfo> stream_target_info_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ChromeResourceDispatcherHostDelegate);
 };
 
 #endif  // CHROME_BROWSER_LOADER_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_