The fallback implementation currently returns "...(fallback from
unknown)" since ImplemenationName() is deprecated. Fix this by
using GetDecoderInfo() to determine the implementation name.
Bug: webrtc:12271
Change-Id: Ifa1d97678cd1bf05d9b5a10b73da23c4d54a1e05
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/257901
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Johannes Kron <kron@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36440}
96dbc60704