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

content/browser/renderer_host/p2p/socket_host_udp_unittest.cc

Index: content/browser/renderer_host/p2p/socket_host_udp_unittest.cc
diff --git a/content/browser/renderer_host/p2p/socket_host_udp_unittest.cc b/content/browser/renderer_host/p2p/socket_host_udp_unittest.cc
index f01e1e40c7c4aef6d2192c20c855340c217fecc5..b0f397bc4db53c880def39a6a0d21b86c9491b06 100644
--- a/content/browser/renderer_host/p2p/socket_host_udp_unittest.cc
+++ b/content/browser/renderer_host/p2p/socket_host_udp_unittest.cc
@@ -113,6 +113,8 @@ class FakeDatagramServerSocket : public net::DatagramServerSocket {
 
   int SetSendBufferSize(int32_t size) override { return net::OK; }
 
+  int SetDoNotFragment() override { return net::OK; }
+
   void ReceivePacket(const net::IPEndPoint& address, std::vector<char> data) {
     if (!recv_callback_.is_null()) {
       int size = std::min(recv_size_, static_cast<int>(data.size()));