Refactor NACK bitrate allocation

webrtc/base/rate_statistics.cc

Index: webrtc/base/rate_statistics.cc
diff --git a/webrtc/base/rate_statistics.cc b/webrtc/base/rate_statistics.cc
index 1fd63cc6d2a071251edb0a9f4f3744fd700571f2..7382619b400c8183ae52596bdbdf78d4353f7da8 100644
--- a/webrtc/base/rate_statistics.cc
+++ b/webrtc/base/rate_statistics.cc
@@ -77,6 +77,12 @@ rtc::Optional<uint32_t> RateStatistics::Rate(int64_t now_ms) {
       static_cast<uint32_t>(accumulated_count_ * scale + 0.5f));
 }
 
+rtc::Optional<uint32_t> RateStatistics::Rate(int64_t now_ms) const {

[danilchap, 2016/06/28 14:26:17]

May be it would be slightly cleaner if only one Rate function would remain
(const version) and const_cast would be used to call EraseOld.

[sprang_webrtc, 2016/07/04 09:33:03]

Done.

+  // Yes, this is ugly, but it's preferable to declaring all internal state
+  // mutable...
+  return const_cast<RateStatistics*>(this)->Rate(now_ms);
+}
+
 void RateStatistics::EraseOld(int64_t now_ms) {
   if (!IsInitialized())
     return;