Add missing overrides in VideoEncoder proxies/adapters

Add:
1. OnPacketLossRateUpdate
2. OnRttUpdate
3. OnLossNotification

Add them to:
1. VideoEncoderSoftwareFallbackWrapper
2. SimulcastEncoderAdapter
3. MultiplexEncoderAdapter

Bug: None
Change-Id: I4b0799f7d8c19211741f48da87106daccd39af95
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/144030
Commit-Queue: Elad Alon <eladalon@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28423}
diff --git a/api/video_codecs/video_encoder_software_fallback_wrapper.cc b/api/video_codecs/video_encoder_software_fallback_wrapper.cc
index a6eaed1..1a683eb 100644
--- a/api/video_codecs/video_encoder_software_fallback_wrapper.cc
+++ b/api/video_codecs/video_encoder_software_fallback_wrapper.cc
@@ -90,11 +90,18 @@
       EncodedImageCallback* callback) override;
 
   int32_t Release() override;
+
   int32_t Encode(const VideoFrame& frame,
                  const std::vector<VideoFrameType>* frame_types) override;
-  // TOD(eladalon): Add OnPacketLossRateUpdate, OnRttUpdate and
-  // OnLossNotification.
+
+  void OnPacketLossRateUpdate(float packet_loss_rate) override;
+
+  void OnRttUpdate(int64_t rtt_ms) override;
+
+  void OnLossNotification(const LossNotification& loss_notification) override;
+
   void SetRates(const RateControlParameters& parameters) override;
+
   EncoderInfo GetEncoderInfo() const override;
 
  private:
@@ -278,6 +285,26 @@
     fallback_encoder_->SetRates(parameters);
 }
 
+void VideoEncoderSoftwareFallbackWrapper::OnPacketLossRateUpdate(
+    float packet_loss_rate) {
+  VideoEncoder* encoder =
+      use_fallback_encoder_ ? fallback_encoder_.get() : encoder_.get();
+  encoder->OnPacketLossRateUpdate(packet_loss_rate);
+}
+
+void VideoEncoderSoftwareFallbackWrapper::OnRttUpdate(int64_t rtt_ms) {
+  VideoEncoder* encoder =
+      use_fallback_encoder_ ? fallback_encoder_.get() : encoder_.get();
+  encoder->OnRttUpdate(rtt_ms);
+}
+
+void VideoEncoderSoftwareFallbackWrapper::OnLossNotification(
+    const LossNotification& loss_notification) {
+  VideoEncoder* encoder =
+      use_fallback_encoder_ ? fallback_encoder_.get() : encoder_.get();
+  encoder->OnLossNotification(loss_notification);
+}
+
 VideoEncoder::EncoderInfo VideoEncoderSoftwareFallbackWrapper::GetEncoderInfo()
     const {
   EncoderInfo fallback_encoder_info = fallback_encoder_->GetEncoderInfo();