Add a build flag to configure bundling of HSTS preload list

net/features.gni

 # Copyright 2016 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.
 
 import("//build/config/features.gni")
 
 declare_args() {
   # If true, prune things down as needed for proto-quic build.
   is_proto_quic = false
 
@@ skipping 12 matching lines @@
   use_kerberos = !is_ios && !is_chromecast
 
   # Do not disable brotli filter by default.
   disable_brotli_filter = false
 
   # Multicast DNS.
   enable_mdns = is_win || is_linux
 
   # Reporting not used on iOS.
   enable_reporting = !is_ios
+
+  # Whether transport security preload list should be included. This flag should
+  # not be changed without examining the risks and tradeoffs.
+  # HTTP strict transport security (HSTS) is defined in
+  # http://tools.ietf.org/html/ietf-websec-strict-transport-sec.
+  # Changing this flag to false will disable bundling of
+  # net/http/transport_security_state_static.json, which enforces domains-
+  # configured HSTS settings.
+  include_transport_security_state_preload_list = true
 }