Record the time duration for establishing proxy connection

net/http/http_proxy_client_socket_wrapper.h

 // Copyright 2015 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_HTTP_HTTP_PROXY_CLIENT_SOCKET_WRAPPER_H_
 #define NET_HTTP_HTTP_PROXY_CLIENT_SOCKET_WRAPPER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 187 matching lines @@
   CompletionCallback connect_callback_;
 
   SpdyStreamRequest spdy_stream_request_;
 
   scoped_refptr<HttpAuthController> http_auth_controller_;
 
   NetLogWithSource net_log_;
 
   base::OneShotTimer connect_timer_;
 
+  // Time when the connection to the proxy was started.
+  base::TimeTicks connect_start_time_;
+
   DISALLOW_COPY_AND_ASSIGN(HttpProxyClientSocketWrapper);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_PROXY_CLIENT_SOCKET_WRAPPER_H_