Revert of Remove unnecessary interface TelephoneEventHandler

webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc b/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
index cd25d9ef87aebbf51fa59718c4b5573dd5cf340c..38b2830b79cbe9c3e903044b8c3b2eb746d49fdb 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
@@ -25,7 +25,9 @@
 
 RTPReceiverAudio::RTPReceiverAudio(RtpData* data_callback)
     : RTPReceiverStrategy(data_callback),
+      TelephoneEventHandler(),
       last_received_frequency_(8000),
+      telephone_event_forward_to_decoder_(false),
       telephone_event_payload_type_(-1),
       cng_nb_payload_type_(-1),
       cng_wb_payload_type_(-1),
@@ -38,6 +40,19 @@
       current_remote_energy_() {
   last_payload_.Audio.channels = 1;
   memset(current_remote_energy_, 0, sizeof(current_remote_energy_));
+}
+
+// Outband TelephoneEvent(DTMF) detection
+void RTPReceiverAudio::SetTelephoneEventForwardToDecoder(
+    bool forward_to_decoder) {
+  rtc::CritScope lock(&crit_sect_);
+  telephone_event_forward_to_decoder_ = forward_to_decoder;
+}
+
+// Is forwarding of outband telephone events turned on/off?
+bool RTPReceiverAudio::TelephoneEventForwardToDecoder() const {
+  rtc::CritScope lock(&crit_sect_);
+  return telephone_event_forward_to_decoder_;
 }
 
 bool RTPReceiverAudio::TelephoneEventPayloadType(
@@ -341,6 +356,10 @@
 
     // check if it's a DTMF event, hence something we can playout
     if (telephone_event_packet) {
+      if (!telephone_event_forward_to_decoder_) {
+        // don't forward event to decoder
+        return 0;
+      }
       std::set<uint8_t>::iterator first =
           telephone_event_reported_.begin();
       if (first != telephone_event_reported_.end() && *first > 15) {