TWCC-PLR -based FecController doesn’t need smoothing

webrtc/common_audio/smoothing_filter.cc

Index: webrtc/common_audio/smoothing_filter.cc
diff --git a/webrtc/common_audio/smoothing_filter.cc b/webrtc/common_audio/smoothing_filter.cc
index 2ab25981f1e3af4b4777026f212591094f75a78c..f0441e5d943259dd86b9ab6ae6d00de932bf1906 100644
--- a/webrtc/common_audio/smoothing_filter.cc
+++ b/webrtc/common_audio/smoothing_filter.cc
@@ -111,8 +111,6 @@ void SmoothingFilterImpl::ExtrapolateLastSample(int64_t time_ms) {
   last_state_time_ms_ = time_ms;
 }
 
-}  // namespace webrtc
-
 // Appendix: derivation of extrapolation during initialization phase.
 // (LaTeX syntax)
 // Assuming
@@ -140,3 +138,22 @@ void SmoothingFilterImpl::ExtrapolateLastSample(int64_t time_ms) {
 //     \frac{\gamma^m - \gamma^n}{1 - \gamma}
 //     &= \frac{T^\frac{T-m}{T} - T^\frac{T-n}{T}}{T - T^{1-\frac{1}{T}}}
 //   \end{align}
+
+NullSmoothingFilter::NullSmoothingFilter() = default;
+
+NullSmoothingFilter::~NullSmoothingFilter() = default;
+
+void NullSmoothingFilter::AddSample(float sample) {
+  last_sample_ = rtc::Optional<float>(sample);
+}
+
+rtc::Optional<float> NullSmoothingFilter::GetAverage() {
+  return last_sample_;
+}
+
+bool NullSmoothingFilter::SetTimeConstantMs(int time_constant_ms) {
+  RTC_NOTREACHED();
+  return false;
+}
+
+}  // namespace webrtc