Fix for scenario where m-line is revived after being set to port 0.

talk/app/webrtc/rtpreceiver.h

Index: talk/app/webrtc/rtpreceiver.h
diff --git a/talk/app/webrtc/rtpreceiver.h b/talk/app/webrtc/rtpreceiver.h
index a93ccbcbfe89ca63ad650879f95453714709bb6d..f50b61e366e62336cdf2ca6a3809450369ed4422 100644
--- a/talk/app/webrtc/rtpreceiver.h
+++ b/talk/app/webrtc/rtpreceiver.h
@@ -61,13 +61,17 @@ class AudioRtpReceiver : public ObserverInterface,
     return track_.get();
   }
 
+  cricket::MediaType media_type() const override {
+    return cricket::MEDIA_TYPE_AUDIO;
+  }
+
   std::string id() const override { return id_; }
 
   void Stop() override;
 
- private:
-  void Reconfigure();
+  void Reconfigure() override;
 
+ private:
   std::string id_;
   rtc::scoped_refptr<AudioTrackInterface> track_;
   uint32_t ssrc_;
@@ -88,10 +92,16 @@ class VideoRtpReceiver : public rtc::RefCountedObject<RtpReceiverInterface> {
     return track_.get();
   }
 
+  cricket::MediaType media_type() const override {
+    return cricket::MEDIA_TYPE_VIDEO;
+  }
+
   std::string id() const override { return id_; }
 
   void Stop() override;
 
+  void Reconfigure() override;
+
  private:
   std::string id_;
   rtc::scoped_refptr<VideoTrackInterface> track_;