Changes in effective degradation preference is now done directly
on the VideoStreamAdapter. This means that the
DegradationPreferenceListener class can be removed.
Bug: webrtc:11700
Change-Id: I9ce4b627de0279df5ef2e5a38435a6d352fbb135
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/178609
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Evan Shrubsole <eshr@google.com>
Cr-Commit-Position: refs/heads/master@{#31642}