- Remove calls to VoEDtmf from WVoE/MC.
- Flatten logic and make the relevant calls on VoE::Channel from AudioSendStream::SendTelephoneEvent().
- Store current payload type for telephone events in WVoMC, instead of setting it on the Channel. This should be refactored to be an AudioSendStream::Config parameter when we redo WVoMC::SetSendCodecs().

BUG=webrtc:4690
R=pthatcher@webrtc.org, tina.legrand@webrtc.org

Review URL: https://codereview.webrtc.org/1491743004 .

Cr-Original-Commit-Position: refs/heads/master@{#10895}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: b572768efbc1e52b97a5ad98932c667956aba4b8
diff --git a/voice_engine/channel_proxy.h b/voice_engine/channel_proxy.h
index 6b916a5..3668de4 100644
--- a/voice_engine/channel_proxy.h
+++ b/voice_engine/channel_proxy.h
@@ -51,6 +51,9 @@
   virtual int32_t GetSpeechOutputLevelFullRange() const;
   virtual uint32_t GetDelayEstimate() const;
 
+  virtual bool SetSendTelephoneEventPayloadType(int payload_type);
+  virtual bool SendTelephoneEventOutband(uint8_t event, uint32_t duration_ms);
+
  private:
   Channel* channel() const;