Introduce NetworkDelegate's implementation in extensions.

extensions/browser/api/extensions_api_client.cc

 // Copyright 2014 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 "extensions/browser/api/extensions_api_client.h"
 
 #include "base/logging.h"
+#include "extensions/browser/api/web_request/web_request_event_router_delegate.h"
 #include "extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest_delegate.h"
 #include "extensions/browser/guest_view/web_view/web_view_permission_helper_delegate.h"
 
 namespace extensions {
 class AppViewGuestDelegate;
 
 namespace {
 ExtensionsAPIClient* g_instance = NULL;
 }  // namespace
 
@@ skipping 32 matching lines @@
 }
 
 WebViewPermissionHelperDelegate* ExtensionsAPIClient::
     CreateWebViewPermissionHelperDelegate(
         WebViewPermissionHelper* web_view_permission_helper) const {
   return new WebViewPermissionHelperDelegate(web_view_permission_helper);
 }
 
 WebRequestEventRouterDelegate*
 ExtensionsAPIClient::CreateWebRequestEventRouterDelegate() const {
-  return NULL;
+  return new WebRequestEventRouterDelegate();
 }
 
 scoped_refptr<ContentRulesRegistry>
 ExtensionsAPIClient::CreateContentRulesRegistry(
     content::BrowserContext* browser_context,
     RulesCacheDelegate* cache_delegate) const {
   return scoped_refptr<ContentRulesRegistry>();
 }
 
 }  // namespace extensions