This way VP8Decoder and DecoderFallback would use propagated instead of global field trials.
Bug: webrtc:15791, webrtc:10335
Change-Id: I5ad5fae38f5b9379bc6376334562c154fbc56e39
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/340040
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Auto-Submit: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41763}