Removed theme functions

A few core theme functions have been removed to make the theme layer in Drupal 8 simpler and easier to extend with a custom layer like in a true framework.

• theme_user_list() - this function was just a wrapper around theme_item_list().
• All theme_pager_*() functions that were rendering links to pages have been removed. theme_pager() now builds a render array, where links are expressed as '#type' => 'link' elements.
• theme_book_title_link() - replaced by l()

…and a few more (feel free to add follow-up issues to this list).

theme_user_list()

user_list is now exposed as a renderable array and there's no theme_user_list() in core anymore.

Drupal 7

function user_block_view($delta = '') {
  global $user;

  $block = array();

  switch ($delta) {
  //...
    case 'new':
      if (user_access('access content')) {
        // Retrieve a list of new users who have subsequently accessed the site successfully.
        $items = db_query_range('SELECT uid, name FROM {users} WHERE status <> 0 AND access <> 0 ORDER BY created DESC', 0, variable_get('user_block_whois_new_count', 5))->fetchAll();
        $output = theme('user_list', array('users' => $items));

        $block['subject'] = t('Who\'s new');
        $block['content'] = $output;
     }
    //...
  }

  return $block;
}

Drupal 8

user_list has become item_list now.

function user_block_view($delta = '') {
  $block['content'] = array(
    '#theme' => 'item_list__user__new',
    '#items' => array(),
  );
}

function user_block_view($delta = '') {
  $block['subject'] = t('Who\'s online');
  $block['content'] = array(
    '#theme' => 'item_list__user__online',
    '#items' => array(),
    '#prefix' => '<p>' . format_plural($authenticated_count, 'There is currently 1 user online.', 'There are currently @count users online.') . '</p>',
  );