Remove the unused QUIC port selection logic.

ios/chrome/browser/ios_chrome_io_thread.mm

 // 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.
 
 #include "ios/chrome/browser/ios_chrome_io_thread.h"
 
 #include <stddef.h>
 
 #include <utility>
 #include <vector>
@@ skipping 378 matching lines @@
   if (command_line.HasSwitch(switches::kIOSTestingFixedHttpPort)) {
     params_.testing_fixed_http_port =
         GetSwitchValueAsInt(command_line, switches::kIOSTestingFixedHttpPort);
   }
   if (command_line.HasSwitch(switches::kIOSTestingFixedHttpsPort)) {
     params_.testing_fixed_https_port =
         GetSwitchValueAsInt(command_line, switches::kIOSTestingFixedHttpsPort);
   }
 
   params_.ignore_certificate_errors = false;
-  params_.enable_quic_port_selection = false;
   params_.enable_user_alternate_protocol_ports = false;
 
   std::string quic_user_agent_id = ::GetChannelString();
   if (!quic_user_agent_id.empty())
     quic_user_agent_id.push_back(' ');
   quic_user_agent_id.append(
       version_info::GetProductNameAndVersionForUserAgent());
   quic_user_agent_id.push_back(' ');
   quic_user_agent_id.append(web::BuildOSCpuInfo());
 
@@ skipping 154 matching lines @@
 
   globals->system_http_network_session.reset(
       new net::HttpNetworkSession(system_params));
   globals->system_http_transaction_factory.reset(
       new net::HttpNetworkLayer(globals->system_http_network_session.get()));
   context->set_http_transaction_factory(
       globals->system_http_transaction_factory.get());
 
   return context;
 }