Set target frame rate of spatial layer equal to minimum of two: maximum frame rate of layer (SpatialLayer::maxFramerate) and maximum frame rate of codec (VideoCodec::maxFramerate). Bug: webrtc:9740, webrtc:9739, chromium:882358 Change-Id: I34f36e7fd2889f0417474347abab5327fa2d9d7c Reviewed-on: https://webrtc-review.googlesource.com/99501 Commit-Queue: Sergey Silkin <ssilkin@webrtc.org> Reviewed-by: Erik Språng <sprang@webrtc.org> Cr-Commit-Position: refs/heads/master@{#24686}