Roll src/net/third_party/quiche/src/ 600a04528..d57d3f905 (4 commits)

https://quiche.googlesource.com/quiche.git/+log/600a04528655..d57d3f905ac4

$ git log 600a04528..d57d3f905 --date=short --no-merges --format='%ad %ae %s'
2019-07-16 fkastenholz IETF CONNECTION CLOSE code is varint encoded
2019-07-16 fayang gfe-relnote: Deprecate  gfe2_reloadable_flag_quic_check_connected_before_flush.
2019-07-15 bnc Use GetReadableRegion() instead of PeekRegion() in QuicReceiveControlStream::OnDataAvailable().
2019-07-15 ianswett Deprecate rolled-back flag gfe2_reloadable_flag_quic_optimize_inflight_check in the false position because it will be replaced with IETF recovery's PTO.

Created with:
  roll-dep src/net/third_party/quiche/src src/third_party/quic_trace/src

Change-Id: I136174350a9afae833444074859ec0bafed7d405
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1704714
Auto-Submit: Bence Béky <bnc@chromium.org>
Commit-Queue: Zhongyi Shi <zhongyi@chromium.org>
Reviewed-by: Zhongyi Shi <zhongyi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#678049}

DEPS

@@ -283,7 +283,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.
-  'quiche_revision': '600a045286553a6484b45452be8d985cb3c7e031',
+  'quiche_revision': 'd57d3f905ac470ad0b31352907668c22ffb0c0b4',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling ios_webkit
   # and whatever else without interference from each other.

net/quic/quic_flags_list.h

@@ -109,10 +109,6 @@ QUIC_FLAG(double, FLAGS_quic_pace_time_into_future_srtt_fraction, 0.125f)
 // Mechanism to override version label and ALPN for IETF interop.
 QUIC_FLAG(int32_t, FLAGS_quic_ietf_draft_version, 0)
 
-// Stop checking QuicUnackedPacketMap::HasUnackedRetransmittableFrames and
-// instead rely on the existing check that bytes_in_flight > 0
-QUIC_FLAG(bool, FLAGS_quic_reloadable_flag_quic_optimize_inflight_check, false)
-
 // If true, stop resetting ideal_next_packet_send_time_ in pacing sender.
 QUIC_FLAG(
     bool,
@@ -229,11 +225,6 @@ QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_conservative_cwnd_and_pacing_gains,
           false)
 
-// If true, check whether connection is connected before flush.
-QUIC_FLAG(bool,
-          FLAGS_quic_reloadable_flag_quic_check_connected_before_flush,
-          true)
-
 // When true, QuicConnectionId will allocate long connection IDs on the heap
 // instead of inline in the object.
 QUIC_FLAG(bool, FLAGS_quic_restart_flag_quic_use_allocated_connection_ids, true)