Remove unused method OutputMixer::PlayDtmfTone() and infrastructure.

webrtc/voice_engine/output_mixer.h

Index: webrtc/voice_engine/output_mixer.h
diff --git a/webrtc/voice_engine/output_mixer.h b/webrtc/voice_engine/output_mixer.h
index 3287860f7f34b46751a2f15797afcc2b62f3b3f3..ae2f53fdb9d7d8197b89c25b0c2a554e8fcfcd93 100644
--- a/webrtc/voice_engine/output_mixer.h
+++ b/webrtc/voice_engine/output_mixer.h
@@ -17,7 +17,6 @@
 #include "webrtc/modules/audio_conference_mixer/include/audio_conference_mixer.h"
 #include "webrtc/modules/audio_conference_mixer/include/audio_conference_mixer_defines.h"
 #include "webrtc/modules/utility/include/file_recorder.h"
-#include "webrtc/voice_engine/dtmf_inband.h"
 #include "webrtc/voice_engine/level_indicator.h"
 #include "webrtc/voice_engine/voice_engine_defines.h"
 
@@ -50,9 +49,6 @@ public:
 
     int DeRegisterExternalMediaProcessing();
 
-    // VoEDtmf
-    int PlayDtmfTone(uint8_t eventCode, int lengthMs, int attenuationDb);
-
     int32_t MixActiveChannels();
 
     int32_t DoOperationsOnCombinedSignal(bool feed_data_to_apm);
@@ -102,7 +98,6 @@ public:
 
 private:
     OutputMixer(uint32_t instanceId);
-    int InsertInbandDtmfTone();
 
     // uses
     Statistics* _engineStatisticsPtr;
@@ -118,7 +113,6 @@ private:
     // Converts mixed audio to the audio processing rate.
     PushResampler<int16_t> audioproc_resampler_;
     AudioLevel _audioLevel;    // measures audio level for the combined signal
-    DtmfInband _dtmfGenerator;
     int _instanceId;
     VoEMediaProcess* _externalMediaCallbackPtr;
     bool _externalMedia;