Add a new QuicFlagSaver class for saving/restoring the values of QUIC flags in tests.

net/quic/core/quic_flags.cc

Index: net/quic/core/quic_flags.cc
diff --git a/net/quic/core/quic_flags.cc b/net/quic/core/quic_flags.cc
index 15c68ff8dc43274b4dace7dd4f2fba4a25fac361..f53537db09014c8b05bd33fc0b5c19a9f2adfd6b 100644
--- a/net/quic/core/quic_flags.cc
+++ b/net/quic/core/quic_flags.cc
@@ -4,164 +4,6 @@
 
 #include "net/quic/core/quic_flags.h"
 
-// If true, it will return as soon as an error is detected while validating
-// CHLO.
-bool FLAGS_use_early_return_when_verifying_chlo = true;
-
-// If true, QUIC BBR congestion control may be enabled via Finch and/or via QUIC
-// connection options.
-bool FLAGS_quic_allow_bbr = false;
-
-// Time period for which a given connection_id should live in the time-wait
-// state.
-int64_t FLAGS_quic_time_wait_list_seconds = 200;
-
-// Currently, this number is quite conservative.  The max QPS limit for an
-// individual server silo is currently set to 1000 qps, though the actual max
-// that we see in the wild is closer to 450 qps.  Regardless, this means that
-// the longest time-wait list we should see is 200 seconds * 1000 qps = 200000.
-// Of course, there are usually many queries per QUIC connection, so we allow a
-// factor of 3 leeway.
-//
-// Maximum number of connections on the time-wait list. A negative value implies
-// no configured limit.
-int64_t FLAGS_quic_time_wait_list_max_connections = 600000;
-
-// Enables server-side support for QUIC stateless rejects.
-bool FLAGS_enable_quic_stateless_reject_support = true;
-
-// This flag is not in use, just to keep consistency for shared code.
-bool FLAGS_quic_always_log_bugs_for_tests = true;
-
-// If true, multipath is enabled for the connection.
-bool FLAGS_quic_enable_multipath = false;
-
-// If true, require handshake confirmation for QUIC connections, functionally
-// disabling 0-rtt handshakes.
-// TODO(rtenneti): Enable this flag after CryptoServerTest's are fixed.
-bool FLAGS_quic_require_handshake_confirmation = false;
-
-// If true, Cubic's epoch is shifted when the sender is application-limited.
-bool FLAGS_shift_quic_cubic_epoch_when_app_limited = true;
-
-// If true, QUIC will measure head of line (HOL) blocking due between
-// streams due to packet losses on the headers stream.  The
-// measurements will be surfaced via UMA histogram
-// Net.QuicSession.HeadersHOLBlockedTime.
-bool FLAGS_quic_measure_headers_hol_blocking_time = true;
-
-// If true, disable pacing in QUIC.
-bool FLAGS_quic_disable_pacing_for_perf_tests = false;
-
-// If true, Close the connection instead of writing unencrypted stream data.
-bool FLAGS_quic_never_write_unencrypted_data = true;
-
-// If true, QUIC connections can do bandwidth resumption with an initial window
-// of < 10 packets.
-bool FLAGS_quic_no_lower_bw_resumption_limit = true;
-
-// Use largest acked in the most recent ack instead of largest acked ever in
-// loss recovery.
-bool FLAGS_quic_loss_recovery_use_largest_acked = true;
-
-// Only set one alarm for sending at once, either the send alarm or
-// retransmission alarm.  Disabled because it breaks QUIC time loss detection.
-bool FLAGS_quic_only_one_sending_alarm = false;
-
-// If true, QUIC public reset packets will have the \"pre-v33\" public header
-// flags.
-bool FLAGS_quic_use_old_public_reset_packets = true;
-
-// If true, QUIC will use cheap stateless rejects without creating a full
-// connection.
-bool FLAGS_quic_use_cheap_stateless_rejects = false;
-
-// If true, QUIC respect HTTP2 SETTINGS frame rather than always close the
-// connection.
-bool FLAGS_quic_respect_http2_settings_frame = true;
-
-// If true, enables QUIC_VERSION_35.
-bool FLAGS_quic_enable_version_35 = true;
-
-// If true, re-enables QUIC_VERSION_36.
-bool FLAGS_quic_enable_version_36 = true;
-
-// If true, enables QUIC_VERSION_36.
-bool FLAGS_quic_enable_version_36_v2 = false;
-
-// If true, use async codepaths to invoke ProofSource::GetProof.
-bool FLAGS_enable_async_get_proof = false;
-
-// If true, neuter null encrypted packets before sending the next handshake
-// message.
-bool FLAGS_quic_neuter_unencrypted_when_sending = true;
-
-// If true, QuicAlarm::Update will call a faster UpdateImpl implementation
-// instead of canceling and reregistering the alarm.
-bool FLAGS_quic_change_alarms_efficiently = true;
-
-// If true, requires handshake confirmations for all QUIC handshakes with
-// versions less than 33.
-bool FLAGS_quic_require_handshake_confirmation_pre33 = false;
-
-// If true, fix a bug with which QuicStreamSequencerBuffer can\'t release block
-// memory in time.
-bool FLAGS_quic_sequencer_buffer_retire_block_in_time = true;
-
-// Remove obsolete code to force QUIC to go forward secure, now that the server
-// immediately goes forward secure.
-bool FLAGS_quic_remove_obsolete_forward_secure = true;
-
-// If true, close QUIC connection explicitly on write error due to packet being
-// too large.
-bool FLAGS_quic_close_connection_on_packet_too_large = true;
-
-// If true, close the write side of a QUIC spdy stream when all queued bytes
-// have been written and a FIN has been sent.
-bool FLAGS_quic_close_stream_after_writing_queued_data = true;
-
-// If true, close connection with QUIC_TOO_MANY_FRAME_GAPS error when number of
-// gaps in QuicStreamSequenceBuffer exceeds allowed limit.
-bool FLAGS_quic_limit_frame_gaps_in_buffer = true;
-
-// If true, v33 QUIC client uses 1 bit to specify 8-byte connection id in public
-// flag.
-bool FLAGS_quic_remove_v33_hacks = true;
-
-// If true, use the CHLO packet size, not message size when determining how
-// large a REJ can be.
-bool FLAGS_quic_use_chlo_packet_size = false;
-
-// If true, defer creation of new connection till its CHLO arrives.
-bool FLAGS_quic_buffer_packet_till_chlo = false;
-
-// If true, the connection will check whether it is application-limited, and
-// notify the congestion controller about it.
-bool FLAGS_quic_enable_app_limited_check = true;
-
-// Deprecate QuicPacketCreator::next_packet_number_length_ because it's no
-// longer necessary.
-bool FLAGS_quic_simple_packet_number_length_2 = true;
-
-// If true, disables QUIC version less than 32.
-bool FLAGS_quic_disable_pre_32 = false;
-
-// If true, QUIC will enforce the MTU limit for connections that may require a
-// small MTU.
-bool FLAGS_quic_enforce_mtu_limit = false;
-
-// Disable MTU probing if MTU probe causes ERR_MSG_TOO_BIG instead of aborting
-// the connection.
-bool FLAGS_graceful_emsgsize_on_mtu_probe = true;
-
-// If true, do not force sending ack when connection is closed because of
-// message too long (EMSGSIZE) write error.
-bool FLAGS_quic_do_not_send_ack_on_emsgsize = true;
-
-// If true, postpone multipath flag validation to ProcessValidatedPacket.
-bool FLAGS_quic_postpone_multipath_flag_validation = true;
-
-// If true, set a QUIC connection's last_sent_for_timeout_ to the send time of
-// the first packet sent after receiving a packet, even if the sent packet is
-// a retransmission
-bool FLAGS_quic_better_last_send_for_timeout = true;
+#define QUIC_FLAG(type, flag, value) type flag = value;
+#include "net/quic/core/quic_flags_list.h"
+#undef QUIC_FLAG