Refactor NACK bitrate allocation

webrtc/voice_engine/channel.cc

Index: webrtc/voice_engine/channel.cc
diff --git a/webrtc/voice_engine/channel.cc b/webrtc/voice_engine/channel.cc
index 943a04572be088689cb655578001dd533703c0b7..861efde3f395ec1c682b33295169ad19593e152c 100644
--- a/webrtc/voice_engine/channel.cc
+++ b/webrtc/voice_engine/channel.cc
@@ -149,6 +149,20 @@ class RtpPacketSenderProxy : public RtpPacketSender {
     }
   }
 
+  bool AllocateRetransmissionBitrate(size_t bytes) override {
+    rtc::CritScope lock(&crit_);
+    if (rtp_packet_sender_)
+      return rtp_packet_sender_->AllocateRetransmissionBitrate(bytes);
+    return false;
+  }
+
+  int CurrentRetransmissionBitrate() override {
+    rtc::CritScope lock(&crit_);
+    if (rtp_packet_sender_)
+      return rtp_packet_sender_->CurrentRetransmissionBitrate();
+    return 0;
+  }
+
  private:
   rtc::ThreadChecker thread_checker_;
   rtc::CriticalSection crit_;