Create the SrtpTransportInterface.

webrtc/api/ortc/ortcfactoryinterface.h

Index: webrtc/api/ortc/ortcfactoryinterface.h
diff --git a/webrtc/api/ortc/ortcfactoryinterface.h b/webrtc/api/ortc/ortcfactoryinterface.h
index 855e3b0b585f00a8caf66e7d30aeb8584b88fb1c..62ed90d06773bdbdc2657d70261044e48b9c16ad 100644
--- a/webrtc/api/ortc/ortcfactoryinterface.h
+++ b/webrtc/api/ortc/ortcfactoryinterface.h
@@ -23,6 +23,7 @@
 #include "webrtc/api/ortc/packettransportinterface.h"
 #include "webrtc/api/ortc/rtptransportcontrollerinterface.h"
 #include "webrtc/api/ortc/rtptransportinterface.h"
+#include "webrtc/api/ortc/srtptransportinterface.h"
 #include "webrtc/api/ortc/udptransportinterface.h"
 #include "webrtc/api/rtcerror.h"
 #include "webrtc/api/rtpparameters.h"
@@ -126,6 +127,14 @@ class OrtcFactoryInterface {
       PacketTransportInterface* rtcp,
       RtpTransportControllerInterface* transport_controller) = 0;
 
+  // Creates an SrtpTransport which is an RTP transport that uses SRTP.
+  virtual RTCErrorOr<std::unique_ptr<SrtpTransportInterface>>
+  CreateSrtpTransport(
+      const RtcpParameters& rtcp_parameters,
+      PacketTransportInterface* rtp,
+      PacketTransportInterface* rtcp,
+      RtpTransportControllerInterface* transport_controller) = 0;
+
   // Returns the capabilities of an RTP sender of type |kind|. These
   // capabilities can be used to determine what RtpParameters to use to create
   // an RtpSender.