Test wiring to DegradationPreference passed to
VideoSendStream::SetSource, but not the adaptation implemented in the
test class FakeVideoCapturer.
Bug: webrtc:6353
Change-Id: Iec2ae89283fb856822ea2829db17eaa02337b467
Reviewed-on: https://webrtc-review.googlesource.com/c/117641
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26278}