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

net/dns/address_sorter_posix_unittest.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/dns/address_sorter_posix.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "net/base/ip_address.h"
@@ skipping 29 matching lines @@
   int Read(IOBuffer*, int, const CompletionCallback&) override {
     NOTIMPLEMENTED();
     return OK;
   }
   int Write(IOBuffer*, int, const CompletionCallback&) override {
     NOTIMPLEMENTED();
     return OK;
   }
   int SetReceiveBufferSize(int32_t) override { return OK; }
   int SetSendBufferSize(int32_t) override { return OK; }
+  int SetDoNotFragment() override { return OK; }
 
   void Close() override {}
   int GetPeerAddress(IPEndPoint* address) const override {
     NOTIMPLEMENTED();
     return OK;
   }
   int GetLocalAddress(IPEndPoint* address) const override {
     if (!connected_)
       return ERR_UNEXPECTED;
     *address = local_endpoint_;
@@ skipping 267 matching lines @@
   AddMapping("4000::1", "4000::10");  // global unicast
   AddMapping("ff32::2", "fe81::20");  // deprecated link-local multicast
   GetSourceInfo("fe81::20")->deprecated = true;
   const char* const addresses[] = { "ff3e::1", "ff32::2", "4000::1", "ff32::1",
                                     "::1", "8.0.0.1", NULL };
   const int order[] = { 4, 3, 0, 2, 1, -1 };
   Verify(addresses, order);
 }
 
 }  // namespace net