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

webrtc/modules/audio_coding/neteq4/neteq_impl.cc

@@ -402,6 +402,11 @@ NetEqBackgroundNoiseMode NetEqImpl::BackgroundNoiseMode() const {
   return background_noise_->mode();
 }
 
+const SyncBuffer* NetEqImpl::sync_buffer_for_test() const {
+  CriticalSectionScoped lock(crit_sect_.get());
+  return sync_buffer_.get();
+}
+
 // Methods below this line are private.
 
 int NetEqImpl::InsertPacketInternal(const WebRtcRTPHeader& rtp_header,