static stubAbort_() {
    /* eslint-disable no-restricted-syntax */
    const addSourceBuffer = MediaSource.prototype.addSourceBuffer;
    MediaSource.prototype.addSourceBuffer = function(...varArgs) {
      const sourceBuffer = addSourceBuffer.apply(this, varArgs);
      sourceBuffer.abort = function() {}; // Stub out for buggy implementations.
      return sourceBuffer;
    };
    /* eslint-enable no-restricted-syntax */
  }
Stub out abort().  On some buggy MSE implementations, calling abort()
causes various problems.

@private