drupalSettings.user.uid added to page even if there is no other JS; drupal.node-new-comments-link lib added for anon users

#1991684: Node history markers (comment & node "new" indicator, "x new comments" links) forces render caching to be per user introduced the regression.

/**
 * Implements hook_page_build().
 */
function user_page_build(&$page) {
  $path = drupal_get_path('module', 'user');
  $page['#attached']['css'][$path . '/css/user.module.css'] = array('every_page' => TRUE);

  // Provide the user ID in drupalSettings to allow JavaScript code to customize
  // the experience for the end user, rather than the server side, which would
  // break the render cache.
  global $user;
  $page['#attached']['js'][] = array(
    'type' => 'setting',
    'data' => array('user' => array(
      'uid' => $user->id(),
    )),
  );
}

Because something is added to the settings array that and do so through drupal_add_js(), the settings array will be added. It doesn't make sense to use a library for the settings here.

It's not too bad since drupalSettings depends on nothing but it still makes the browser run the JS thing for a page that shouldn't need it.

For settings we should use alter since we're able to check if there actually are settings for the page.

Can't you add the permission for anon to comment as well, the isAuthenticated() might get in the way?

Right it's not for posting a new comment, my bad.

aannnd after testing, that works.

postponed #2120457: Add test to guarantee that the Standard profile does not load any JavaScript for anonymous users on critical pages on this one.