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

net/udp/udp_socket_win.h

Index: net/udp/udp_socket_win.h
diff --git a/net/udp/udp_socket_win.h b/net/udp/udp_socket_win.h
index 14b801e36fe4d44e3f807f3464424a95e146656f..2e25b126734cdf21a3c52346224af475f3000566 100644
--- a/net/udp/udp_socket_win.h
+++ b/net/udp/udp_socket_win.h
@@ -124,6 +124,10 @@ class NET_EXPORT UDPSocketWin
   // Returns a net error code.
   int SetSendBufferSize(int32_t size);
 
+  // Configures the socket to set or clear the DF (Do not Fragment) bit on
+  // packets, which prevents routers from fragmenting them.
+  int SetDoNotFragment();
+
   // Returns true if the socket is already connected or bound.
   bool is_connected() const { return is_connected_; }