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

talk/app/webrtc/peerconnectioninterface.h

Index: talk/app/webrtc/peerconnectioninterface.h
diff --git a/talk/app/webrtc/peerconnectioninterface.h b/talk/app/webrtc/peerconnectioninterface.h
index 8f6f7bb3ffc312f032602500e66669a3c1fbd388..521dad26956780472f64bc4e83d895c94e4b4fbc 100644
--- a/talk/app/webrtc/peerconnectioninterface.h
+++ b/talk/app/webrtc/peerconnectioninterface.h
@@ -411,6 +411,9 @@ class PeerConnectionObserver {
   // All Ice candidates have been found.
   virtual void OnIceComplete() {}
 
+  // Called when the ICE connection receiving status changes.
+  virtual void OnIceConnectionReceivingChange(bool receiving) {}
+
  protected:
   // Dtor protected as objects shouldn't be deleted via this interface.
   ~PeerConnectionObserver() {}