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

webrtc/voice_engine/include/voe_codec.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 113 matching lines @@
   // TODO(minyue): Make SetOpusMaxPlaybackRate() pure virtual when
   // fakewebrtcvoiceengine in talk is ready.
   virtual int SetOpusMaxPlaybackRate(int channel, int frequency_hz) {
     return -1;
   }
 
   // If send codec is Opus on a specified |channel|, set its DTX. Returns 0 if
   // success, and -1 if failed.
   virtual int SetOpusDtx(int channel, bool enable_dtx) = 0;
 
+  // If send codec is Opus on a specified |channel|, return its DTX status.
+  // Returns 0 on success, and -1 if failed.
+  virtual int GetOpusDtx(int channel, bool* enabled) { return -1; }

[henrika_webrtc, 2016/07/27 09:32:59]

Why default implementation?

[ivoc, 2016/07/27 09:48:32]

This is a public API, and there is code outside of WebRTC that implements this
interface (for example for tests). When adding functions, I think it's good to
add a default implementation first before all the deriving classes are updated.
I will add a TODO here to remind myself to make it pure virtual later.

+
  protected:
   VoECodec() {}
   virtual ~VoECodec() {}
 };
 
 }  // namespace webrtc
 
 #endif  //  WEBRTC_VOICE_ENGINE_VOE_CODEC_H