Update from chromium https://crrev.com/301315

net/quic/quic_client_session.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_client_session.h"
 
 #include "base/callback_helpers.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
@@ skipping 16 matching lines @@
 #include "net/udp/datagram_client_socket.h"
 
 namespace net {
 
 namespace {
 
 // The length of time to wait for a 0-RTT handshake to complete
 // before allowing the requests to possibly proceed over TCP.
 const int k0RttHandshakeTimeoutMs = 300;
 
+// IPv6 packets have an additional 20 bytes of overhead than IPv4 packets.
+const size_t kAdditionalOverheadForIPv6 = 20;
+
 // Histograms for tracking down the crashes from http://crbug.com/354669
 // Note: these values must be kept in sync with the corresponding values in:
 // tools/metrics/histograms/histograms.xml
 enum Location {
   DESTRUCTOR = 0,
   ADD_OBSERVER = 1,
   TRY_CREATE_STREAM = 2,
   CREATE_OUTGOING_RELIABLE_STREAM = 3,
   NOTIFY_FACTORY_OF_SESSION_CLOSED_LATER = 4,
   NOTIFY_FACTORY_OF_SESSION_CLOSED = 5,
@@ skipping 116 matching lines @@
       server_info_(server_info.Pass()),
       read_pending_(false),
       num_total_streams_(0),
       task_runner_(task_runner),
       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_QUIC_SESSION)),
       logger_(new QuicConnectionLogger(this, net_log_)),
       num_packets_read_(0),
       going_away_(false),
       weak_factory_(this) {
   connection->set_debug_visitor(logger_);
+  IPEndPoint address;
+  if (socket && socket->GetLocalAddress(&address) == OK &&
+      address.GetFamily() == ADDRESS_FAMILY_IPV6) {
+    connection->set_max_packet_length(
+        connection->max_packet_length() - kAdditionalOverheadForIPv6);
+  }
 }
 
 void QuicClientSession::InitializeSession(
     const QuicServerId& server_id,
     QuicCryptoClientConfig* crypto_config,
     QuicCryptoClientStreamFactory* crypto_client_stream_factory) {
   server_host_port_ = server_id.host_port_pair();
   crypto_stream_.reset(
       crypto_client_stream_factory ?
           crypto_client_stream_factory->CreateQuicCryptoClientStream(
@@ skipping 694 matching lines @@
     return;
 
   // TODO(rch): re-enable this code once beta is cut.
   //  if (stream_factory_)
   //    stream_factory_->OnSessionConnectTimeout(this);
   //  CloseAllStreams(ERR_QUIC_HANDSHAKE_FAILED);
   //  DCHECK_EQ(0u, GetNumOpenStreams());
 }
 
 }  // namespace net