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

net/http/http_proxy_client_socket_wrapper.h

 // Copyright 2015 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_HTTP_HTTP_PROXY_CLIENT_SOCKET_WRAPPER_H_
 #define NET_HTTP_HTTP_PROXY_CLIENT_SOCKET_WRAPPER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 96 matching lines @@
 
   // Socket implementation.
   int Read(IOBuffer* buf,
            int buf_len,
            const CompletionCallback& callback) override;
   int Write(IOBuffer* buf,
             int buf_len,
             const CompletionCallback& callback) override;
   int SetReceiveBufferSize(int32_t size) override;
   int SetSendBufferSize(int32_t size) override;
+  int SetDoNotFragment(bool do_not_fragment) override;
   int GetPeerAddress(IPEndPoint* address) const override;
   int GetLocalAddress(IPEndPoint* address) const override;
 
  private:
   enum State {
     STATE_BEGIN_CONNECT,
     STATE_TCP_CONNECT,
     STATE_TCP_CONNECT_COMPLETE,
     STATE_SSL_CONNECT,
     STATE_SSL_CONNECT_COMPLETE,
@@ skipping 77 matching lines @@
   BoundNetLog net_log_;
 
   base::OneShotTimer connect_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpProxyClientSocketWrapper);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_PROXY_CLIENT_SOCKET_WRAPPER_H_