Add a SetDoNotFragment() method to DatagramSocket, and call this for

net/quic/chromium/quic_stream_factory.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/chromium/quic_stream_factory.h"
 
 #include <openssl/aead.h>
 
 #include <algorithm>
 #include <tuple>
@@ skipping 49 matching lines @@
 using NetworkHandle = net::NetworkChangeNotifier::NetworkHandle;
 
 namespace net {
 
 namespace {
 
 enum CreateSessionFailure {
   CREATION_ERROR_CONNECTING_SOCKET,
   CREATION_ERROR_SETTING_RECEIVE_BUFFER,
   CREATION_ERROR_SETTING_SEND_BUFFER,
+  CREATION_ERROR_SETTING_NO_NOT_FRAGMENT,
   CREATION_ERROR_MAX
 };
 
 enum QuicConnectionMigrationStatus {
   MIGRATION_STATUS_NO_MIGRATABLE_STREAMS,
   MIGRATION_STATUS_ALREADY_MIGRATED,
   MIGRATION_STATUS_INTERNAL_ERROR,
   MIGRATION_STATUS_TOO_MANY_CHANGES,
   MIGRATION_STATUS_SUCCESS,
   MIGRATION_STATUS_NON_MIGRATABLE_STREAM,
@@ skipping 1642 matching lines @@
     HistogramCreateSessionFailure(CREATION_ERROR_CONNECTING_SOCKET);
     return rv;
   }
 
   rv = socket->SetReceiveBufferSize(socket_receive_buffer_size_);
   if (rv != OK) {
     HistogramCreateSessionFailure(CREATION_ERROR_SETTING_RECEIVE_BUFFER);
     return rv;
   }
 
+  rv = socket->SetDoNotFragment();
+  if (rv != OK) {
+    HistogramCreateSessionFailure(CREATION_ERROR_SETTING_NO_NOT_FRAGMENT);
+    return rv;
+  }
+
   // Set a buffer large enough to contain the initial CWND's worth of packet
   // to work around the problem with CHLO packets being sent out with the
   // wrong encryption level, when the send buffer is full.
   rv = socket->SetSendBufferSize(kMaxPacketSize * 20);
   if (rv != OK) {
     HistogramCreateSessionFailure(CREATION_ERROR_SETTING_SEND_BUFFER);
     return rv;
   }
 
   socket->GetLocalAddress(&local_address_);
@@ skipping 300 matching lines @@
   // Since the session was active, there's no longer an
   // HttpStreamFactoryImpl::Job running which can mark it broken, unless the TCP
   // job also fails. So to avoid not using QUIC when we otherwise could, we mark
   // it as recently broken, which means that 0-RTT will be disabled but we'll
   // still race.
   http_server_properties_->MarkAlternativeServiceRecentlyBroken(
       alternative_service);
 }
 
 }  // namespace net