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

net/url_request/url_request_throttler_manager.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_THROTTLER_MANAGER_H_
 #define NET_URL_REQUEST_URL_REQUEST_THROTTLER_MANAGER_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 123 matching lines @@
   // Set of hosts that have opted out.
   OptOutHosts opt_out_hosts_;
 
   // This keeps track of how many requests have been made. Used with
   // GarbageCollectEntries.
   unsigned int requests_since_last_gc_;
 
   // Valid after construction.
   GURL::Replacements url_id_replacements_;
 
-  // Whether we would like to reject outgoing HTTP requests during the back-off
-  // period.
-  bool enforce_throttling_;
-
   // Certain tests do not obey the net component's threading policy, so we
   // keep track of whether we're being used by tests, and turn off certain
   // checks.
   //
   // TODO(joi): See if we can fix the offending unit tests and remove this
   // workaround.
   bool enable_thread_checks_;
 
   // Initially false, switches to true once we have logged because of back-off
   // being disabled for localhost.
   bool logged_for_localhost_disabled_;
 
   // NetLog to use, if configured.
   BoundNetLog net_log_;
 
   // Valid once we've registered for network notifications.
   base::PlatformThreadId registered_from_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(URLRequestThrottlerManager);
 };
 
 }  // namespace net
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_THROTTLER_MANAGER_H_