Perform ClientHello padding if the field trial is enabled

net/http/http_network_session.h

Index: net/http/http_network_session.h
diff --git a/net/http/http_network_session.h b/net/http/http_network_session.h
index 68b10db4a24860954fb02748e19f2f505788696a..b98b7a302d4e0ecc6f6df44f71efa36a76437b7b 100644
--- a/net/http/http_network_session.h
+++ b/net/http/http_network_session.h
@@ -52,6 +52,7 @@ class QuicServerInfoFactory;
 class SOCKSClientSocketPool;
 class SSLClientSocketPool;
 class SSLConfigService;
+class SSLSocketConfigService;
 class TransportClientSocketPool;
 class TransportSecurityState;
 
@@ -129,6 +130,7 @@ class NET_EXPORT HttpNetworkSession
     QuicVersionVector quic_supported_versions;
     QuicTagVector quic_connection_options;
     ProxyDelegate* proxy_delegate;
+    SSLSocketConfigService* ssl_socket_config_service;
   };
 
   enum SocketPoolType {