Code review comment for lp:~thomas-voss/media-hub/introduce-video-sink-interface

Looks good, just 1 inline comment below. Also, make sure to rebase with trunk changes. This would be the very first MR I'd like to see get put into a silo so that I can test it well. This is a nice limited-scope MR but still is important. I want to try to avoid having to test all of the MRs combined in one silo, but instead would like to incrementally test one or 2 MRs at a time and land, then test 1 or two more and land, etc.