Disable SPDY/3.1.

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 @@
   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());
 
-  network_session_configurator::ParseFieldTrials(true, true, quic_user_agent_id,
+  network_session_configurator::ParseFieldTrials(true, quic_user_agent_id,
                                                  &params_);
   const version_info::Channel channel = ::GetChannel();
   if (channel == version_info::Channel::UNKNOWN ||
       channel == version_info::Channel::CANARY ||
       channel == version_info::Channel::DEV) {
     globals_->url_request_backoff_manager.reset(
         new net::URLRequestBackoffManager());
   }
 
   // InitSystemRequestContext turns right around and posts a task back
@@ skipping 149 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;
 }