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

net/udp/udp_socket_unittest.cc

 // Copyright (c) 2012 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.
 
 #include "net/udp/udp_socket.h"
 
 #include "net/udp/udp_client_socket.h"
 #include "net/udp/udp_server_socket.h"
 
 #include "base/bind.h"
@@ skipping 563 matching lines @@
   CreateUDPAddress("127.0.0.1", 0, &bind_address);
   UDPServerSocket server(NULL, NetLog::Source());
   int rv = server.Listen(bind_address);
   EXPECT_THAT(rv, IsOk());
 
   IPEndPoint peer_address;
   rv = server.GetPeerAddress(&peer_address);
   EXPECT_EQ(rv, ERR_SOCKET_NOT_CONNECTED);
 }
 
+TEST_F(UDPSocketTest, ClientSetDoNotFragment) {
+  UDPClientSocket client(DatagramSocket::DEFAULT_BIND, RandIntCallback(), NULL,
+                         NetLog::Source());
+  IPAddress ip_address;
+  EXPECT_TRUE(ip_address.AssignFromIPLiteral("127.0.0.1"));

[mmenke, 2016/08/12 21:55:49]

Should we do it with IPv6, too?  The IPv6 path is more interesting.   Could just
use a loop, or duplicate the test.

[Ryan Hamilton, 2016/08/12 22:15:26]

Sure. Done.

+  IPEndPoint remote_address(ip_address, 80);
+  int rv = client.Connect(remote_address);
+  EXPECT_THAT(rv, IsOk());
+
+#if defined(OS_MACOSX)
+  EXPECT_EQ(ERR_NOT_IMPLEMENTED, client.SetDoNotFragment());
+#else
+  EXPECT_EQ(OK, client.SetDoNotFragment());
+#endif
+}
+
+TEST_F(UDPSocketTest, ServerSetDoNotFragment) {
+  IPEndPoint bind_address;
+  CreateUDPAddress("127.0.0.1", 0, &bind_address);
+  UDPServerSocket server(NULL, NetLog::Source());
+  int rv = server.Listen(bind_address);
+  EXPECT_THAT(rv, IsOk());
+
+#if defined(OS_MACOSX)
+  EXPECT_EQ(ERR_NOT_IMPLEMENTED, server.SetDoNotFragment());
+#else
+  EXPECT_EQ(OK, server.SetDoNotFragment());
+#endif
+}
+
 // Close the socket while read is pending.
 TEST_F(UDPSocketTest, CloseWithPendingRead) {
   IPEndPoint bind_address;
   CreateUDPAddress("127.0.0.1", 0, &bind_address);
   UDPServerSocket server(NULL, NetLog::Source());
   int rv = server.Listen(bind_address);
   EXPECT_THAT(rv, IsOk());
 
   TestCompletionCallback callback;
   IPEndPoint from;
@@ skipping 265 matching lines @@
   g_expected_traffic_type = QOSTrafficTypeExcellentEffort;
   EXPECT_THAT(client.SetDiffServCodePoint(DSCP_NO_CHANGE), IsOk());
   g_expected_dscp = DSCP_DEFAULT;
   g_expected_traffic_type = QOSTrafficTypeBestEffort;
   EXPECT_THAT(client.SetDiffServCodePoint(DSCP_DEFAULT), IsOk());
   client.Close();
 }
 #endif
 
 }  // namespace net