abort_(contentType) {
    const sourceBuffer = this.sourceBuffers_.get(contentType);
    // Save the append window, which is reset on abort().
    const appendWindowStart = sourceBuffer.appendWindowStart;
    const appendWindowEnd = sourceBuffer.appendWindowEnd;

    // This will not trigger an 'updateend' event, since nothing is happening.
    // This is only to reset MSE internals, not to abort an actual operation.
    sourceBuffer.abort();

    // Restore the append window.
    sourceBuffer.appendWindowStart = appendWindowStart;
    sourceBuffer.appendWindowEnd = appendWindowEnd;

    // Fake an 'updateend' event to resolve the operation.
    this.onUpdateEnd_(contentType);
  }
Call abort() on the SourceBuffer.
This resets MSE's last_decode_timestamp on all track buffers, which should
trigger the splicing logic for overlapping segments.
@param {shaka.util.ManifestParserUtils.ContentType} contentType
@private