Regression test for issue where Opus DTX status was being forgotten.

webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.cc

Index: webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.cc
diff --git a/webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.cc b/webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.cc
index edafbbdf39d9f64449395209bde4941a2df8d66f..51b0843e09792cdbf84d0d62fa71c01ed5a2539d 100644
--- a/webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.cc
+++ b/webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.cc
@@ -152,6 +152,10 @@ bool AudioEncoderOpus::SetDtx(bool enable) {
   return RecreateEncoderInstance(conf);
 }
 
+bool AudioEncoderOpus::GetDtx() {

[minyue-webrtc, 2016/07/25 16:13:01]

why to add another function since dtx_enabled() exists?

[ivoc, 2016/07/25 17:11:09]

The function needs to be on the AudioEncoder interface so it can be called from
the outside world, and dtx_enabled() is not on that interface. I can merge the
two functions into one, but I think it should be called GetDtx(), since it fits
better with the naming system on the AudioEncoder interface. 

[minyue-webrtc, 2016/07/26 09:37:01]

Ok. Can you remove AudioEncoderOpus::dtx_enabled()

[ivoc, 2016/07/26 12:28:31]

It's already gone :-)

[minyue-webrtc, 2016/07/26 15:04:54]

Oh, yes, sorry. I missed that one

+  return dtx_enabled();
+}
+
 bool AudioEncoderOpus::SetApplication(Application application) {
   auto conf = config_;
   switch (application) {