A couple methods in AppendPipeline were returning GstFlowReturn despite there being no codepath (sans assertions) where values other than GST_FLOW_OK are returned. Therefore, it makes sense to just make these methods return void.
Created attachment 360656 [details] Patch
Comment on attachment 360656 [details] Patch Clearing flags on attachment: 360656 Committed r240784: <https://trac.webkit.org/changeset/240784>
All reviewed patches have been landed. Closing bug.