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

net/socket/tcp_client_socket.cc

 // Copyright (c) 2013 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/socket/tcp_client_socket.h"
 
 #include <utility>
 
 #include "base/callback_helpers.h"
 #include "base/logging.h"
@@ skipping 291 matching lines @@
 }
 
 int TCPClientSocket::SetReceiveBufferSize(int32_t size) {
   return socket_->SetReceiveBufferSize(size);
 }
 
 int TCPClientSocket::SetSendBufferSize(int32_t size) {
     return socket_->SetSendBufferSize(size);
 }
 
+int TCPClientSocket::SetDoNotFragment(bool do_not_fragment) {
+  return socket_->SetSendBufferSize(do_not_fragment);

[Jeremy Dorfman, 2016/08/10 23:56:57]

Copy/paste error?

[Ryan Hamilton, 2016/08/11 19:47:31]

Indeed, but I've reverted this change since I made SetDoNotFragment UDP
specific.

+}
+
 bool TCPClientSocket::SetKeepAlive(bool enable, int delay) {
   return socket_->SetKeepAlive(enable, delay);
 }
 
 bool TCPClientSocket::SetNoDelay(bool no_delay) {
   return socket_->SetNoDelay(no_delay);
 }
 
 void TCPClientSocket::GetConnectionAttempts(ConnectionAttempts* out) const {
   *out = connection_attempts_;
@@ skipping 65 matching lines @@
 void TCPClientSocket::EmitTCPMetricsHistogramsOnDisconnect() {
   base::TimeDelta rtt;
   if (socket_->GetEstimatedRoundTripTime(&rtt)) {
     UMA_HISTOGRAM_CUSTOM_TIMES("Net.TcpRtt.AtDisconnect", rtt,
                                base::TimeDelta::FromMilliseconds(1),
                                base::TimeDelta::FromMinutes(10), 100);
   }
 }
 
 }  // namespace net