The Media Source standard long ago changed to disallow ambiguously defined behavior involving asynchronous range removals: * SourceBuffer.abort() no longer aborts SourceBuffer.remove() operations * Setting MediaSource.duration can no longer truncate currently buffered media Exceptions will be thrown in both of these cases now. Safari and Firefox have long shipped this behavior, Chromium is the last browser remaining with the old behavior. Use counters show ~0.001%-0.005% of page loads hit the deprecated behavior. Primarily small Russian sites. If a site hits this issue, playback may now break. Usage of abort() cancelling removals is increasing, so it's prudent to resolve this deprecation before more incompatible usage appears.
Chromium should comply with the spec and shipping behavior in Firefox and Safari to avoid future interop issues while usage remains low.