Add OnLossNotification() to VideoEncoder and Vp8FrameBufferController

Bug: webrtc:10501
Change-Id: I33e8bfcf16cf24aadcfdf214d7d9bcd495bf9348
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/131021
Commit-Queue: Elad Alon <eladalon@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27449}
diff --git a/api/video_codecs/vp8_frame_buffer_controller.h b/api/video_codecs/vp8_frame_buffer_controller.h
index 7f4c282..f3f6745 100644
--- a/api/video_codecs/vp8_frame_buffer_controller.h
+++ b/api/video_codecs/vp8_frame_buffer_controller.h
@@ -14,7 +14,9 @@
 #include <memory>
 #include <vector>
 
+#include "absl/types/optional.h"
 #include "api/video_codecs/video_codec.h"
+#include "api/video_codecs/video_encoder.h"
 #include "api/video_codecs/vp8_frame_config.h"
 
 namespace webrtc {
@@ -137,6 +139,10 @@
 
   // Called by the encoder when the round trip time changes.
   virtual void OnRttUpdate(int64_t rtt_ms) = 0;
+
+  // Called when a loss notification is received.
+  virtual void OnLossNotification(
+      const VideoEncoder::LossNotification loss_notification) = 0;
 };
 
 // Interface for a factory of Vp8FrameBufferController instances.