Introduce a delegate to avoid hardcoding "chrome-extension" in net/.

net/url_request/url_request_test_util.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 NET_URL_REQUEST_URL_REQUEST_TEST_UTIL_H_
 #define NET_URL_REQUEST_URL_REQUEST_TEST_UTIL_H_
 #pragma once
 
 #include <stdlib.h>
 
@@ skipping 226 matching lines @@
       const net::AuthChallengeInfo& auth_info,
       const AuthCallback& callback,
       net::AuthCredentials* credentials) OVERRIDE;
   virtual bool OnCanGetCookies(const net::URLRequest& request,
                                const net::CookieList& cookie_list) OVERRIDE;
   virtual bool OnCanSetCookie(const net::URLRequest& request,
                               const std::string& cookie_line,
                               net::CookieOptions* options) OVERRIDE;
   virtual bool OnCanAccessFile(const net::URLRequest& request,
                                const FilePath& path) const OVERRIDE;
+  virtual bool OnCanThrottleRequest(
+      const net::URLRequest& request) const OVERRIDE;
 
   void InitRequestStatesIfNew(int request_id);
 
   int last_error_;
   int error_count_;
   int created_requests_;
   int destroyed_requests_;
   int completed_requests_;
   int cookie_options_bit_mask_;
   int blocked_get_cookies_count_;
@@ skipping 30 matching lines @@
 
  private:
   static std::string value_;
   const std::string old_value_;
   const std::string new_value_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedCustomUrlRequestTestHttpHost);
 };
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_TEST_UTIL_H_