QUIC - Add back to code to experiment with delay_tcp_race. By default,

net/url_request/url_request_context_builder.cc

Index: net/url_request/url_request_context_builder.cc
diff --git a/net/url_request/url_request_context_builder.cc b/net/url_request/url_request_context_builder.cc
index 0d59128b00dea1e684c4f6b6d9f7d160919ad8e4..3710daf14eea65dc5cdfc6089181d20094d01faf 100644
--- a/net/url_request/url_request_context_builder.cc
+++ b/net/url_request/url_request_context_builder.cc
@@ -186,6 +186,7 @@ URLRequestContextBuilder::HttpNetworkSessionParams::HttpNetworkSessionParams()
       enable_alternative_service_with_different_host(false),
       enable_quic(false),
       quic_max_server_configs_stored_in_properties(0),
+      quic_delay_tcp_race(true),
       quic_max_number_of_lossy_connections(0),
       quic_prefer_aes(false),
       quic_packet_loss_threshold(1.0f),
@@ -419,6 +420,8 @@ std::unique_ptr<URLRequestContext> URLRequestContextBuilder::Build() {
   network_session_params.enable_quic = http_network_session_params_.enable_quic;
   network_session_params.quic_max_server_configs_stored_in_properties =
       http_network_session_params_.quic_max_server_configs_stored_in_properties;
+  network_session_params.quic_delay_tcp_race =
+      http_network_session_params_.quic_delay_tcp_race;
   network_session_params.quic_max_number_of_lossy_connections =
       http_network_session_params_.quic_max_number_of_lossy_connections;
   network_session_params.quic_packet_loss_threshold =