Allow p2p UDP packages to set DSCP

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 807b403034e0ee4be53882ceb3142ea8ef7c2c70..3f57cf924cf13a0ec08ae899b676181797ed7e99 100644
--- a/net/udp/udp_socket_win.h
+++ b/net/udp/udp_socket_win.h
@@ -151,6 +151,10 @@ class NET_EXPORT UDPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe) {
   // other applications on the same host. See MSDN: http://goo.gl/6vqbj
   int SetMulticastLoopbackMode(bool loopback);
 
+  // Set the differentiated services flags on outgoing packets. May not
+  // do anything on some platforms.
+  int SetToS(DiffServCodePoint dscp);
+
  private:
   enum SocketOptions {
     SOCKET_OPTION_REUSE_ADDRESS  = 1 << 0,
@@ -207,6 +211,9 @@ class NET_EXPORT UDPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe) {
   // Cannot be used after Bind().
   int multicast_time_to_live_;
 
+  // Differentiated Services Code Point.
+  DiffServCodePoint dscp_;
+
   // How to do source port binding, used only when UDPSocket is part of
   // UDPClientSocket, since UDPServerSocket provides Bind.
   DatagramSocket::BindType bind_type_;