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..58cdc46b5b49f3674797bf89e09beb7699ff886f 100644
--- a/webrtc/modules/rtp_rtcp/include/receive_statistics.h
+++ b/webrtc/modules/rtp_rtcp/include/receive_statistics.h
@@ -33,7 +33,7 @@ class StreamStatistician {
   virtual void GetReceiveStreamDataCounters(
       StreamDataCounters* data_counters) const = 0;
 
-  virtual uint32_t BitrateReceived() const = 0;
+  virtual uint32_t BitrateReceived() = 0;
 
   // Returns true if the packet with RTP header |header| is likely to be a
   // retransmitted packet, false otherwise.
@@ -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;