Add flakiness check if there is no received packets in a certain period.

webrtc/p2p/base/session.h

Index: webrtc/p2p/base/session.h
diff --git a/webrtc/p2p/base/session.h b/webrtc/p2p/base/session.h
index 318a7888dac67cce8bc05c6ebbedd2c672e719fc..6214dad0b1239491ad307d554fb90462570fc4e6 100644
--- a/webrtc/p2p/base/session.h
+++ b/webrtc/p2p/base/session.h
@@ -368,6 +368,9 @@ class BaseSession : public sigslot::has_slots<>,
   virtual void OnTransportReadable(Transport* transport) {
   }
 
+  virtual void OnTransportReceiving(Transport* transport) {
+  }
+
   // Called when a transport has found its steady-state connections.
   virtual void OnTransportCompleted(Transport* transport) {
   }