Add a build flag to configure bundling of HSTS preload list

net/features.gni

Index: net/features.gni
diff --git a/net/features.gni b/net/features.gni
index 95c718ebadb7edb2a72d3363d3936374c4e4fb3b..96a7a3a1c42ba8cc9685b724da577275ed29e244 100644
--- a/net/features.gni
+++ b/net/features.gni
@@ -30,4 +30,12 @@ declare_args() {
 
   # Reporting not used on iOS.
   enable_reporting = !is_ios
+
+  # Includes the transport security state preload list. This list includes
+  # mechanisms (e.g. HSTS, HPKP) to enforce trusted connections to a significant
+  # set of hardcoded domains. While this list has a several hundred KB of binary
+  # size footprint, this flag should not be disabled unless the embedder is
+  # willing to take the responsibility to make sure that all important
+  # connections use HTTPS.
+  include_transport_security_state_preload_list = true
 }