Refactor NACK bitrate allocation

webrtc/modules/rtp_rtcp/include/receive_statistics.h

Index: webrtc/modules/rtp_rtcp/include/receive_statistics.h
diff --git a/webrtc/modules/rtp_rtcp/include/receive_statistics.h b/webrtc/modules/rtp_rtcp/include/receive_statistics.h
index cc21e22df50f78fe7fda32f67bcc99857ce3e4bc..90a848ad6335bd7584a67e013b2d7e7c7a7d820f 100644
--- a/webrtc/modules/rtp_rtcp/include/receive_statistics.h
+++ b/webrtc/modules/rtp_rtcp/include/receive_statistics.h
@@ -46,7 +46,7 @@ class StreamStatistician {
 
 typedef std::map<uint32_t, StreamStatistician*> StatisticianMap;
 
-class ReceiveStatistics : public Module {
+class ReceiveStatistics {
  public:
   virtual ~ReceiveStatistics() {}
 
@@ -89,8 +89,6 @@ class NullReceiveStatistics : public ReceiveStatistics {
                          size_t packet_length) override;
   StatisticianMap GetActiveStatisticians() const override;
   StreamStatistician* GetStatistician(uint32_t ssrc) const override;
-  int64_t TimeUntilNextProcess() override;
-  void Process() override;
   void SetMaxReorderingThreshold(int max_reordering_threshold) override;
   void RegisterRtcpStatisticsCallback(
       RtcpStatisticsCallback* callback) override;