Add back pipelining after M17 branch point.

chrome/browser/chrome_browser_main.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/chrome_browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 271 matching lines @@
         &value);
     net::SpdySessionPool::set_max_sessions_per_domain(value);
   }
 
   SetDnsCertProvenanceCheckerFactory(CreateChromeDnsCertProvenanceChecker);
 
   if (parsed_command_line.HasSwitch(switches::kEnableWebSocketOverSpdy)) {
     // Enable WebSocket over SPDY.
     net::WebSocketJob::set_websocket_over_spdy_enabled(true);
   }
+
+  if (parsed_command_line.HasSwitch(switches::kEnableHttpPipelining))
+    net::HttpStreamFactory::set_http_pipelining_enabled(true);
 }
 
 void InitializeURLRequestThrottlerManager(net::NetLog* net_log) {
   net::URLRequestThrottlerManager::GetInstance()->set_enable_thread_checks(
       true);
 
   // TODO(joi): Passing the NetLog here is temporary; once I switch the
   // URLRequestThrottlerManager to be part of the URLRequestContext it will
   // come from there. Doing it this way for now (2011/5/12) to try to fail
   // fast in case A/B experiment gives unexpected results.
@@ skipping 1853 matching lines @@
   if (env->GetVar(chrome::kPreReadEnvironmentVariable, &pre_read) &&
       (pre_read == "0" || pre_read == "1")) {
     std::string uma_name(name);
     uma_name += "_PreRead";
     uma_name += pre_read == "1" ? "Enabled" : "Disabled";
     AddPreReadHistogramTime(uma_name.c_str(), time);
   }
 #endif
 #endif
 }