It appears that the official chrome webstore extension by Rob W is outdated. It was last updated in 2019. 

const viewerOutputName = "viewer.js";
  const viewerFileConfig = createWebpackConfig(
    defines,
    {
      filename: viewerOutputName,
    },
    {
      defaultPreferencesDir: options.defaultPreferencesDir,
    }
  );
  return gulp
    .src("./web/viewer.js")
    .pipe(webpack2Stream(viewerFileConfig))
    .pipe(replaceNonWebpackImport());
}
function createComponentsBundle(defines) {