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

net/udp/datagram_socket.h

Index: net/udp/datagram_socket.h
diff --git a/net/udp/datagram_socket.h b/net/udp/datagram_socket.h
index f0e9fa10baa7fb181b9b2cc6810459c6c31359d6..ab6594028237558194939d903a0cd870f0334512 100644
--- a/net/udp/datagram_socket.h
+++ b/net/udp/datagram_socket.h
@@ -34,6 +34,10 @@ class NET_EXPORT_PRIVATE DatagramSocket {
   // (similar to getsockname)
   virtual int GetLocalAddress(IPEndPoint* address) const = 0;
 
+  // Configures the socket to set the DF (Do not Fragment) bit on packets,
+  // which prevents routers from fragmenting them.

[Jeremy Dorfman, 2016/08/12 17:23:41]

Perhaps worth noting that this may not be available depending on the OS.

[Ryan Hamilton, 2016/08/12 17:40:52]

Done.

+  virtual int SetDoNotFragment() = 0;
+
   // Gets the NetLog for this socket.
   virtual const BoundNetLog& NetLog() const = 0;
 };