It read from simulcast_layers[0] even if vector is empty.
Bug: none
Change-Id: I293890feda70022beae4247ab10cf8182b4cf4a5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/209706
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33391}