net: Move DiffServCodePoint enum out of net_util.h.

This patch moves DiffServCodePoint enum into its own header file under
net/udp/diff_serv_code_point.h, to help breaking up net_util.h.

BUG=488531
[email protected],[email protected]
[email protected],[email protected],[email protected]

Review URL: https://codereview.chromium.org/1396733002

Cr-Commit-Position: refs/heads/master@{#353133}
diff --git a/net/net.gypi b/net/net.gypi
index a6e27b3..4d446b0 100644
--- a/net/net.gypi
+++ b/net/net.gypi
@@ -1144,6 +1144,7 @@
       'udp/datagram_client_socket.h',
       'udp/datagram_server_socket.h',
       'udp/datagram_socket.h',
+      'udp/diff_serv_code_point.h',
       'udp/udp_client_socket.cc',
       'udp/udp_client_socket.h',
       'udp/udp_net_log_parameters.cc',