Experiment with HSTS preload list filtering.

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
 
   # Disables support for file URLs.  File URL support requires use of icu.
   disable_file_support = false
 
   # WebSockets and socket stream code are not used on iOS and are optional in
   # cronet.
   enable_websockets = !is_ios
   disable_ftp_support = is_ios || is_chromecast
 
   # Enable Kerberos authentication. It is disabled by default on iOS,
   # Chromecast, at least for now. This feature needs configuration (krb5.conf
   # and so on). On Chrome OS it is only supported on Active Directory
   # managed devices.
   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
+
+  # The level of filtering for the HSTS preload list:
+  #  2: Heavy filtering; filter everything except entries that are needed for
+  #                      all targets to build and pass tests.
+  #  1: Moderate filtering; only the above and specificly marked entries are
+  #                         included.
+  #  0: No filtering; all entries are included.
+  hsts_preload_list_filter_level = 1  # Testing
 }