Disable QUIC v29 and earlier. Protected by FLAGS_quic_disable_pre_30.

net/quic/quic_protocol.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_protocol.h"
 
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "net/quic/quic_flags.h"
 #include "net/quic/quic_utils.h"
@@ skipping 161 matching lines @@
 }
 
 QuicVersionVector QuicSupportedVersions() {
   QuicVersionVector supported_versions;
   for (size_t i = 0; i < arraysize(kSupportedQuicVersions); ++i) {
     supported_versions.push_back(kSupportedQuicVersions[i]);
   }
   return supported_versions;
 }
 
+QuicVersionVector FilterSupportedVersions(QuicVersionVector versions) {
+  QuicVersionVector filtered_versions(versions.size());
+  filtered_versions.clear();  // Guaranteed by spec not to change capacity.
+  for (QuicVersion version : versions) {
+    if (!FLAGS_quic_disable_pre_30 || version >= QUIC_VERSION_30) {
+      filtered_versions.push_back(version);
+    }
+  }
+  return filtered_versions;
+}
+
 QuicTag QuicVersionToQuicTag(const QuicVersion version) {
   switch (version) {
     case QUIC_VERSION_25:
       return MakeQuicTag('Q', '0', '2', '5');
     case QUIC_VERSION_26:
       return MakeQuicTag('Q', '0', '2', '6');
     case QUIC_VERSION_27:
       return MakeQuicTag('Q', '0', '2', '7');
     case QUIC_VERSION_28:
       return MakeQuicTag('Q', '0', '2', '8');
@@ skipping 656 matching lines @@
       is_unackable(false),
       has_crypto_handshake(has_crypto_handshake),
       num_padding_bytes(num_padding_bytes),
       retransmission(0) {}
 
 TransmissionInfo::TransmissionInfo(const TransmissionInfo& other) = default;
 
 TransmissionInfo::~TransmissionInfo() {}
 
 }  // namespace net