Configure VoE NACK through AudioSendStream::Config, for send streams.

BUG=webrtc:4690

Review-Url: https://codereview.webrtc.org/1955363003
Cr-Original-Commit-Position: refs/heads/master@{#13136}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 971cab0d93823af9a991aa8901eda75f574e0974
diff --git a/voice_engine/channel_proxy.h b/voice_engine/channel_proxy.h
index 8159606..69d4f11 100644
--- a/voice_engine/channel_proxy.h
+++ b/voice_engine/channel_proxy.h
@@ -48,6 +48,7 @@
   virtual void SetRTCPStatus(bool enable);
   virtual void SetLocalSSRC(uint32_t ssrc);
   virtual void SetRTCP_CNAME(const std::string& c_name);
+  virtual void SetNACKStatus(bool enable, int max_packets);
   virtual void SetSendAbsoluteSenderTimeStatus(bool enable, int id);
   virtual void SetSendAudioLevelIndicationStatus(bool enable, int id);
   virtual void SetReceiveAbsoluteSenderTimeStatus(bool enable, int id);