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

net/udp/udp_server_socket.h

Index: net/udp/udp_server_socket.h
diff --git a/net/udp/udp_server_socket.h b/net/udp/udp_server_socket.h
index a0b4852b958740e9d3fb6c6d0fb1d3eee4cbf934..38a8e7bddaf81eb56bbff080d614fed53c5f2227 100644
--- a/net/udp/udp_server_socket.h
+++ b/net/udp/udp_server_socket.h
@@ -36,6 +36,7 @@ class NET_EXPORT UDPServerSocket : public DatagramServerSocket {
              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;