update neteq 4 to facilitate NACK

BUG=
R=turaj@webrtc.org, turajs@google.com

Review URL: https://webrtc-codereview.appspot.com/2008004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4637 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq4/interface/neteq.h b/webrtc/modules/audio_coding/neteq4/interface/neteq.h
index 824b17b..1f1ee67 100644
--- a/webrtc/modules/audio_coding/neteq4/interface/neteq.h
+++ b/webrtc/modules/audio_coding/neteq4/interface/neteq.h
@@ -233,6 +233,10 @@
                                       int* current_memory_size_bytes,
                                       int* max_memory_size_bytes) const = 0;
 
+  // Get sequence number and timestamp of the latest RTP.
+  // This method is to facilitate NACK.
+  virtual int DecodedRtpInfo(int* sequence_number, uint32_t* timestamp) = 0;
+
  protected:
   NetEq() {}