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

remoting/protocol/ssl_hmac_channel_authenticator.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 "remoting/protocol/ssl_hmac_channel_authenticator.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 113 matching lines @@
   int SetReceiveBufferSize(int32_t size) override {
     NOTREACHED();
     return net::ERR_FAILED;
   }
 
   int SetSendBufferSize(int32_t size) override {
     NOTREACHED();
     return net::ERR_FAILED;
   }
 
+  int SetDoNotFragment(bool do_not_fragment) override {
+    NOTREACHED();
+    return net::ERR_FAILED;
+  }
+
   int Connect(const net::CompletionCallback& callback) override {
     NOTREACHED();
     return net::ERR_FAILED;
   }
   void Disconnect() override { socket_.reset(); }
   bool IsConnected() const override { return true; }
   bool IsConnectedAndIdle() const override { return true; }
   int GetPeerAddress(net::IPEndPoint* address) const override {
     // SSL sockets call this function so it must return some result.
     *address = net::IPEndPoint(net::IPAddress::IPv4AllZeros(), 0);
@@ skipping 336 matching lines @@
                           std::move(socket_), std::move(server_context_))));
   }
 }
 
 void SslHmacChannelAuthenticator::NotifyError(int error) {
   base::ResetAndReturn(&done_callback_).Run(error, nullptr);
 }
 
 }  // namespace protocol
 }  // namespace remoting