Split HttpNetworkSession::Params into two structs.

ios/components/io_thread/ios_io_thread.mm

 // Copyright 2017 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/components/io_thread/ios_io_thread.h"
 
 #include <stddef.h>
 
 #include <utility>
 #include <vector>
@@ skipping 495 matching lines @@
   context->set_cookie_store(globals->system_cookie_store.get());
   context->set_channel_id_service(globals->system_channel_id_service.get());
   context->set_network_delegate(globals->system_network_delegate.get());
   context->set_http_user_agent_settings(
       globals->http_user_agent_settings.get());
   context->set_network_quality_estimator(
       globals->network_quality_estimator.get());
 
   context->set_http_server_properties(globals->http_server_properties.get());
 
-  net::HttpNetworkSession::Params system_params(params);
+  net::HttpNetworkSession::Context system_context;
   net::URLRequestContextBuilder::SetHttpNetworkSessionComponents(
-      context, &system_params);
+      context, &system_context);
 
   globals->system_http_network_session.reset(
-      new net::HttpNetworkSession(system_params));
+      new net::HttpNetworkSession(params, system_context));
   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;
 }
 
 }  // namespace io_thread