New NetEq test to verify correct timestamp propagation

BUG=3154
R=turaj@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/11319004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5860 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_impl.h b/webrtc/modules/audio_coding/neteq4/neteq_impl.h
index 511452e..dabf2d6 100644
--- a/webrtc/modules/audio_coding/neteq4/neteq_impl.h
+++ b/webrtc/modules/audio_coding/neteq4/neteq_impl.h
@@ -200,6 +200,9 @@
   // Gets background noise mode.
   virtual NetEqBackgroundNoiseMode BackgroundNoiseMode() const;
 
+  // This accessor method is only intended for testing purposes.
+  virtual const SyncBuffer* sync_buffer_for_test() const;
+
  private:
   static const int kOutputSizeMs = 10;
   static const int kMaxFrameSize = 2880;  // 60 ms @ 48 kHz.