Add time line for acked bitrate.

webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h

Index: webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
diff --git a/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h b/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
index a332d7ce5eeb7a98c3b0495fc51a8593ddbc4492..777219366d587eec185401912782f4daa6d7d34f 100644
--- a/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
+++ b/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
@@ -13,6 +13,7 @@
 
 #include <stddef.h>
 #include <list>
+#include <vector>
 
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/system_wrappers/include/clock.h"
@@ -309,7 +310,8 @@ class TransportFeedbackObserver {
                          size_t length,
                          int probe_cluster_id) = 0;
 
-  virtual void OnTransportFeedback(const rtcp::TransportFeedback& feedback) = 0;
+  virtual std::vector<PacketInfo> OnTransportFeedback(
+      const rtcp::TransportFeedback& feedback) = 0;
 };
 
 class RtcpRttStats {