Refactor NACK bitrate allocation

webrtc/video/video_send_stream_tests.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <algorithm>  // max
@@ skipping 268 matching lines @@
       *statistics = stats_;
       return true;
     }
     void GetDataCounters(size_t* bytes_received,
                          uint32_t* packets_received) const override {
       *bytes_received = 0;
       *packets_received = 0;
     }
     void GetReceiveStreamDataCounters(
         StreamDataCounters* data_counters) const override {}
-    uint32_t BitrateReceived() const override { return 0; }
+    uint32_t BitrateReceived() override { return 0; }
     bool IsRetransmitOfOldPacket(const RTPHeader& header,
                                  int64_t min_rtt) const override {
       return false;
     }
 
     bool IsPacketInOrder(uint16_t sequence_number) const override {
       return true;
     }
 
     RtcpStatistics stats_;
@@ skipping 2076 matching lines @@
         observation_complete_.Set();
       }
     }
   } test;
 
   RunBaseTest(&test);
 }
 #endif  // !defined(RTC_DISABLE_VP9)
 
 }  // namespace webrtc