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

net/udp/udp_server_socket.h

 // 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.
 
 #ifndef NET_SOCKET_UDP_SERVER_SOCKET_H_
 #define NET_SOCKET_UDP_SERVER_SOCKET_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
@@ skipping 18 matching lines @@
   int RecvFrom(IOBuffer* buf,
                int buf_len,
                IPEndPoint* address,
                const CompletionCallback& callback) override;
   int SendTo(IOBuffer* buf,
              int buf_len,
              const IPEndPoint& address,
              const CompletionCallback& callback) override;
   int SetReceiveBufferSize(int32_t size) override;
   int SetSendBufferSize(int32_t size) override;
+  int SetDoNotFragment() override;
   void Close() override;
   int GetPeerAddress(IPEndPoint* address) const override;
   int GetLocalAddress(IPEndPoint* address) const override;
   void UseNonBlockingIO() override;
   const BoundNetLog& NetLog() const override;
   void AllowAddressReuse() override;
   void AllowBroadcast() override;
   int JoinGroup(const IPAddress& group_address) const override;
   int LeaveGroup(const IPAddress& group_address) const override;
   int SetMulticastInterface(uint32_t interface_index) override;
   int SetMulticastTimeToLive(int time_to_live) override;
   int SetMulticastLoopbackMode(bool loopback) override;
   int SetDiffServCodePoint(DiffServCodePoint dscp) override;
   void DetachFromThread() override;
 
  private:
   UDPSocket socket_;
   bool allow_address_reuse_;
   bool allow_broadcast_;
   DISALLOW_COPY_AND_ASSIGN(UDPServerSocket);
 };
 
 }  // namespace net
 
 #endif  // NET_SOCKET_UDP_SERVER_SOCKET_H_