Implement URLRequestBackoffManager for managing Backoff headers

net/url_request/url_request_context_builder.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.
 
 // This class is useful for building a simple URLRequestContext. Most creators
 // of new URLRequestContexts should use this helper class to construct it. Call
 // any configuration params, and when done, invoke Build() to construct the
 // URLRequestContext. This URLRequestContext will own all its own storage.
 //
 // URLRequestContextBuilder and its associated params classes are initially
@@ skipping 163 matching lines @@
   void set_quic_connection_options(
       const QuicTagVector& quic_connection_options) {
     http_network_session_params_.quic_connection_options =
         quic_connection_options;
   }
 
   void set_throttling_enabled(bool throttling_enabled) {
     throttling_enabled_ = throttling_enabled;
   }
 
+  void set_backoff_enabled(bool backoff_enabled) {
+    backoff_enabled_ = backoff_enabled;
+  }
+
   void SetInterceptors(
       ScopedVector<URLRequestInterceptor> url_request_interceptors);
 
   // Override the default in-memory cookie store and channel id service.
   // |cookie_store| must not be NULL. |channel_id_service| may be NULL to
   // disable channel id for this context.
   // Note that a persistent cookie store should not be used with an in-memory
   // channel id service, and one cookie store should not be shared between
   // multiple channel-id stores (or used both with and without a channel id
   // store).
@@ skipping 31 matching lines @@
 #if !defined(DISABLE_FILE_SUPPORT)
   // Include support for file:// requests.
   bool file_enabled_;
 #endif
 #if !defined(DISABLE_FTP_SUPPORT)
   // Include support for ftp:// requests.
   bool ftp_enabled_;
 #endif
   bool http_cache_enabled_;
   bool throttling_enabled_;
+  bool backoff_enabled_;
   bool sdch_enabled_;
 
   scoped_refptr<base::SingleThreadTaskRunner> file_task_runner_;
   HttpCacheParams http_cache_params_;
   HttpNetworkSessionParams http_network_session_params_;
   base::FilePath transport_security_persister_path_;
   scoped_ptr<NetLog> net_log_;
   scoped_ptr<HostResolver> host_resolver_;
   scoped_ptr<ChannelIDService> channel_id_service_;
   scoped_ptr<ProxyConfigService> proxy_config_service_;
   scoped_ptr<ProxyService> proxy_service_;
   scoped_ptr<NetworkDelegate> network_delegate_;
   scoped_refptr<CookieStore> cookie_store_;
   scoped_ptr<FtpTransactionFactory> ftp_transaction_factory_;
   std::vector<SchemeFactory> extra_http_auth_handlers_;
   ScopedVector<URLRequestInterceptor> url_request_interceptors_;
 
   DISALLOW_COPY_AND_ASSIGN(URLRequestContextBuilder);
 };
 
 }  // namespace net
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_CONTEXT_BUILDER_H_