Make RtpSenderAudio not inherit from DtmfQueue

webrtc/modules/rtp_rtcp/source/dtmf_queue.h

Index: webrtc/modules/rtp_rtcp/source/dtmf_queue.h
diff --git a/webrtc/modules/rtp_rtcp/source/dtmf_queue.h b/webrtc/modules/rtp_rtcp/source/dtmf_queue.h
index c0e616f98273ce02abafbdc00fe078c0a45c5e85..fbfc4efcb14fd461b227bb2804afd06ef5b77191 100644
--- a/webrtc/modules/rtp_rtcp/source/dtmf_queue.h
+++ b/webrtc/modules/rtp_rtcp/source/dtmf_queue.h
@@ -19,12 +19,11 @@ namespace webrtc {
 class DTMFqueue {
  public:
   DTMFqueue();
-  virtual ~DTMFqueue();
+  ~DTMFqueue();
 
   int32_t AddDTMF(uint8_t dtmf_key, uint16_t len, uint8_t level);
   int8_t NextDTMF(uint8_t* dtmf_key, uint16_t* len, uint8_t* level);
   bool PendingDTMF();
-  void ResetDTMF();
 
  private:
   rtc::CriticalSection dtmf_critsect_;