Make PacketTransportInternal inherit from PacketTransportInterface.

webrtc/api/ortc/udptransportinterface.h

Index: webrtc/api/ortc/udptransportinterface.h
diff --git a/webrtc/api/ortc/udptransportinterface.h b/webrtc/api/ortc/udptransportinterface.h
index 278107671bbe60ac74d4a23ffc395a4a81268390..9d6866ff628592650eb7ca731db6be0526fe5584 100644
--- a/webrtc/api/ortc/udptransportinterface.h
+++ b/webrtc/api/ortc/udptransportinterface.h
@@ -27,7 +27,7 @@ namespace webrtc {
 //
 // Calling SetRemoteAddress sets the destination of outgoing packets; without a
 // destination, packets can't be sent, but they can be received.
-class UdpTransportInterface : virtual public PacketTransportInterface {
+class UdpTransportInterface : public virtual PacketTransportInterface {
  public:
   // Get the address of the socket allocated for this transport.
   virtual rtc::SocketAddress GetLocalAddress() const = 0;