Revert of Remove obsolete QUIC disabling code.

net/http/http_network_session.cc

Index: net/http/http_network_session.cc
diff --git a/net/http/http_network_session.cc b/net/http/http_network_session.cc
index a4c1913950f22ea0043739f92f5ffb317a66c5b3..b7993218f215447b3eb4d660bc8d6e635e0826c7 100644
--- a/net/http/http_network_session.cc
+++ b/net/http/http_network_session.cc
@@ -65,6 +65,11 @@
 // that seems large enough to receive data at line rate for most connections,
 // and does not consume "too much" memory.
 const int32_t kQuicSocketReceiveBufferSize = 1024 * 1024;  // 1MB
+
+// Number of recent connections to consider for certain thresholds
+// that trigger disabling QUIC.  E.g. disable QUIC if PUBLIC_RESET was
+// received post handshake for at least 2 of 20 recent connections.
+const int32_t kQuicMaxRecentDisabledReasons = 20;
 
 HttpNetworkSession::Params::Params()
     : client_socket_factory(NULL),
@@ -101,6 +106,8 @@
       quic_enable_non_blocking_io(false),
       quic_disable_disk_cache(false),
       quic_prefer_aes(false),
+      quic_max_number_of_lossy_connections(0),
+      quic_packet_loss_threshold(1.0f),
       quic_socket_receive_buffer_size(kQuicSocketReceiveBufferSize),
       quic_delay_tcp_race(true),
       quic_max_server_configs_stored_in_properties(0u),
@@ -110,6 +117,9 @@
       enable_user_alternate_protocol_ports(false),
       quic_crypto_client_stream_factory(
           QuicCryptoClientStreamFactory::GetDefaultFactory()),
+      quic_max_recent_disabled_reasons(kQuicMaxRecentDisabledReasons),
+      quic_threshold_public_resets_post_handshake(0),
+      quic_threshold_timeouts_streams_open(0),
       quic_close_sessions_on_ip_change(false),
       quic_idle_connection_timeout_seconds(kIdleConnectionTimeoutSeconds),
       quic_reduced_ping_timeout_seconds(kPingTimeoutSecs),
@@ -169,6 +179,11 @@
           params.quic_enable_non_blocking_io,
           params.quic_disable_disk_cache,
           params.quic_prefer_aes,
+          params.quic_max_number_of_lossy_connections,
+          params.quic_packet_loss_threshold,
+          params.quic_max_recent_disabled_reasons,
+          params.quic_threshold_public_resets_post_handshake,
+          params.quic_threshold_timeouts_streams_open,
           params.quic_socket_receive_buffer_size,
           params.quic_delay_tcp_race,
           params.quic_max_server_configs_stored_in_properties,
@@ -321,6 +336,9 @@
                    params_.quic_enable_connection_racing);
   dict->SetBoolean("disable_disk_cache", params_.quic_disable_disk_cache);
   dict->SetBoolean("prefer_aes", params_.quic_prefer_aes);
+  dict->SetInteger("max_number_of_lossy_connections",
+                   params_.quic_max_number_of_lossy_connections);
+  dict->SetDouble("packet_loss_threshold", params_.quic_packet_loss_threshold);
   dict->SetBoolean("delay_tcp_race", params_.quic_delay_tcp_race);
   dict->SetInteger("max_server_configs_stored_in_properties",
                    params_.quic_max_server_configs_stored_in_properties);
@@ -335,7 +353,8 @@
                    params_.quic_disable_preconnect_if_0rtt);
   dict->SetBoolean("disable_quic_on_timeout_with_open_streams",
                    params_.disable_quic_on_timeout_with_open_streams);
-  dict->SetBoolean("is_quic_disabled", quic_stream_factory_.IsQuicDisabled());
+  dict->SetString("disabled_reason",
+                  quic_stream_factory_.QuicDisabledReasonString());
   dict->SetBoolean("force_hol_blocking", params_.quic_force_hol_blocking);
   dict->SetBoolean("race_cert_verification",
                    params_.quic_race_cert_verification);