Add FLAGS_quic_crypto_server_config_default_has_chacha20, to allow

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 76d69eca77259cc596054cb25dbd69374e88939b..7fc96daabf3aefaa3693379d7215642804ce8fb9 100644
--- a/net/quic/quic_flags.cc
+++ b/net/quic/quic_flags.cc
@@ -164,3 +164,9 @@ bool FLAGS_quic_crypto_proof_use_ref = true;
 // If on, max number of incoming and outgoing streams will be different.
 // Incoming will be a little higher than outgoing to tolerate race condition.
 bool FLAGS_quic_different_max_num_open_streams = true;
+
+// If true, QUIC should correctly report if it supports ChaCha20. Otherwise,
+// QUIC will lie and claim that it does not support ChaCha20. The primary use
+// case for this is places where ChaCha20 is prohibitively expensive compared to
+// AES-GCM.
+bool FLAGS_quic_crypto_server_config_default_has_chacha20 = true;