Enable NetProxyPreconnects experiment by default

net/http/http_network_session.cc

 // Copyright (c) 2012 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 "net/http/http_network_session.h"
 
 #include <inttypes.h>
 
 #include <utility>
 
@@ skipping 128 matching lines @@
       quic_migrate_sessions_early(false),
       quic_allow_server_migration(false),
       quic_disable_bidirectional_streams(false),
       quic_force_hol_blocking(false),
       quic_race_cert_verification(false),
       quic_do_not_fragment(false),
       quic_do_not_mark_as_broken_on_network_change(false),
       quic_estimate_initial_rtt(false),
       proxy_delegate(nullptr),
       enable_token_binding(false),
-      http_09_on_non_default_ports_enabled(false),
-      restrict_to_one_preconnect_for_proxies(false) {
+      http_09_on_non_default_ports_enabled(false) {
   quic_supported_versions.push_back(QUIC_VERSION_37);
 }
 
 HttpNetworkSession::Params::Params(const Params& other) = default;
 
 HttpNetworkSession::Params::~Params() {}
 
 // TODO(mbelshe): Move the socket factories into HttpStreamFactory.
 HttpNetworkSession::HttpNetworkSession(const Params& params)
     : net_log_(params.net_log),
@@ skipping 313 matching lines @@
       CloseIdleConnections();
       break;
   }
 }
 
 void HttpNetworkSession::OnPurgeMemory() {
   CloseIdleConnections();
 }
 
 }  // namespace net