Remove HTTP pipelining support.

chrome/browser/metrics/network_stats_uploader.h

 // 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.
 
 #ifndef CHROME_BROWSER_METRICS_NETWORK_STATS_UPLOADER_H_
 #define CHROME_BROWSER_METRICS_NETWORK_STATS_UPLOADER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 
 class PrefService;
 class PrefRegistrySimple;
 
 // NetworkStatsUploader implements the collection of various network stats,
 // which is done upon successful transmission of an UMA log.
 class NetworkStatsUploader {
  public:
   NetworkStatsUploader();
   ~NetworkStatsUploader();
 
   // Collects and reports various network stats to external servers.
   void CollectAndReportNetworkStats();
 
  private:
   // The TCP/UDP echo server to collect network connectivity stats.
   std::string network_stats_server_;
 
-  // The HTTP pipelining test server.
-  std::string http_pipelining_test_server_;
-
   DISALLOW_COPY_AND_ASSIGN(NetworkStatsUploader);
 };
 
 #endif  // CHROME_BROWSER_METRICS_NETWORK_STATS_UPLOADER_H_