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

webrtc/voice_engine/include/voe_codec.h

Index: webrtc/voice_engine/include/voe_codec.h
diff --git a/webrtc/voice_engine/include/voe_codec.h b/webrtc/voice_engine/include/voe_codec.h
index 5d94ac27365a91fa3df47901f28ad66422ab7b4f..7fd838b60a0c8068c6319dd14e06fea22936aefb 100644
--- a/webrtc/voice_engine/include/voe_codec.h
+++ b/webrtc/voice_engine/include/voe_codec.h
@@ -131,6 +131,10 @@ class WEBRTC_DLLEXPORT VoECodec {
   // 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; }
+
  protected:
   VoECodec() {}
   virtual ~VoECodec() {}