Relanding https://codereview.webrtc.org/1715883002/ in pieces.

webrtc/modules/audio_coding/test/TwoWayCommunication.cc

Index: webrtc/modules/audio_coding/test/TwoWayCommunication.cc
diff --git a/webrtc/modules/audio_coding/test/TwoWayCommunication.cc b/webrtc/modules/audio_coding/test/TwoWayCommunication.cc
index 3ca7fd217d57592802f6f6ec38a940cf9676f152..161491b061064776bacd71a22ed193047a36c8ca 100644
--- a/webrtc/modules/audio_coding/test/TwoWayCommunication.cc
+++ b/webrtc/modules/audio_coding/test/TwoWayCommunication.cc
@@ -50,14 +50,6 @@ TwoWayCommunication::~TwoWayCommunication() {
   delete _channel_B2A;
   delete _channelRef_A2B;
   delete _channelRef_B2A;
-#ifdef WEBRTC_DTMF_DETECTION
-  if (_dtmfDetectorA != NULL) {
-    delete _dtmfDetectorA;
-  }
-  if (_dtmfDetectorB != NULL) {
-    delete _dtmfDetectorB;
-  }
-#endif
   _inFileA.Close();
   _inFileB.Close();
   _outFileA.Close();