Add a new QUIC ChloExtractor class used by the QuicProxyDispatcher to extract CHLO message from pac…

net/quic/quic_flags.cc

Index: net/quic/quic_flags.cc
diff --git a/net/quic/quic_flags.cc b/net/quic/quic_flags.cc
index a9bf9c14b62bd5c9b651b66c7eb9e08e43146f74..085aa61276b1a14a73e130a86205e407cdfdd529 100644
--- a/net/quic/quic_flags.cc
+++ b/net/quic/quic_flags.cc
@@ -82,6 +82,10 @@ bool FLAGS_quic_cede_correctly = true;
 // AES-GCM.
 bool FLAGS_quic_crypto_server_config_default_has_chacha20 = true;
 
+// If true, uses the new QUIC ChloExtractor for extracting CHLO
+// messages from packets.
+bool FLAGS_quic_use_chlo_extractor = true;
+
 // If true, QUIC will use newly refactored TCP sender code.
 bool FLAGS_quic_use_new_tcp_sender = true;