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

remoting/protocol/ssl_hmac_channel_authenticator.cc

Index: remoting/protocol/ssl_hmac_channel_authenticator.cc
diff --git a/remoting/protocol/ssl_hmac_channel_authenticator.cc b/remoting/protocol/ssl_hmac_channel_authenticator.cc
index 303aea253d1457db7e60352c3c16a0c6080f25dc..e250be8a27ba6ebc29036b0a76d830900466fc20 100644
--- a/remoting/protocol/ssl_hmac_channel_authenticator.cc
+++ b/remoting/protocol/ssl_hmac_channel_authenticator.cc
@@ -131,6 +131,11 @@ class NetStreamSocketAdapter : public net::StreamSocket {
     return net::ERR_FAILED;
   }
 
+  int SetDoNotFragment(bool do_not_fragment) override {
+    NOTREACHED();
+    return net::ERR_FAILED;
+  }
+
   int Connect(const net::CompletionCallback& callback) override {
     NOTREACHED();
     return net::ERR_FAILED;