In flexible mode, use VP9E_GET_SVC_REF_FRAME_CONFIG to get indices of reference frame buffers and buffers update by encoded frame. Set inter_pic_predicted to true only if encoder actually used temporal prediction. Bug: webrtc:9244, webrtc:9270 Change-Id: I4e439abeab9e063d50abdcefc59bf58d6596ea6c Reviewed-on: https://webrtc-review.googlesource.com/74780 Commit-Queue: Sergey Silkin <ssilkin@webrtc.org> Reviewed-by: Åsa Persson <asapersson@webrtc.org> Reviewed-by: Marco Paniconi <marpan@google.com> Cr-Commit-Position: refs/heads/master@{#23410}