Reland of Fix the video buffer size should take rtt into consideration

modules/video_coding/frame_buffer2.cc

Index: modules/video_coding/frame_buffer2.cc
diff --git a/modules/video_coding/frame_buffer2.cc b/modules/video_coding/frame_buffer2.cc
index 50c3763dc1ae687c82713b293ae51c49a07f155b..b4bb0028022f8be34f7db55082512452f9f24900 100644
--- a/modules/video_coding/frame_buffer2.cc
+++ b/modules/video_coding/frame_buffer2.cc
@@ -147,6 +147,8 @@ FrameBuffer::ReturnReason FrameBuffer::NextFrame(
         float rtt_mult = protection_mode_ == kProtectionNackFEC ? 0.0 : 1.0;
         timing_->SetJitterDelay(jitter_estimator_->GetJitterEstimate(rtt_mult));
         timing_->UpdateCurrentDelay(frame->RenderTime(), now_ms);
+      } else {
+        jitter_estimator_->FrameNacked();
       }
 
       // Gracefully handle bad RTP timestamps and render time issues.
@@ -247,6 +249,11 @@ void FrameBuffer::Stop() {
   new_continuous_frame_event_.Set();
 }
 
+void FrameBuffer::UpdateRtt(int64_t rtt_ms) {
+  rtc::CritScope lock(&crit_);
+  jitter_estimator_->UpdateRtt(rtt_ms);
+}
+
 bool FrameBuffer::ValidReferences(const FrameObject& frame) const {
   if (frame.picture_id < 0)
     return false;