Drupal 7 Webform dynamic select option list for providing taxonomy terms as an option list

vocabulary-terms-option-list.php

<?php

/**
 * Implements hook_webform_select_options_info().
 */
function MODULE_webform_select_options_info() {
  $items = array();

  $vocabularies = taxonomy_get_vocabularies();

  foreach( $vocabularies as $vocabulary ){
    $items['vocabulary_'.$vocabulary->machine_name] = array(
      'title' => 'Vocabulary: ' . $vocabulary->name,
      'options callback' => 'vocabulary_terms_webform_select_options_callback',
      'options arguments' => array(
        'vid' => $vocabulary->vid,
      ),
    );
  }

  return $items;
}

/**
 * Option callback for vocabulary select options
 *
 * @param $component
 * @param $flat
 * @param $arguments
 *
 * @return array
 */
function vocabulary_terms_webform_select_options_callback( $component, $flat, $arguments ){
  $options = array();

  $terms = entity_load('taxonomy_term', FALSE, array('vid' => $arguments['vid']));

  foreach( $terms as $term ){
    $options[ $term->tid ] = $term->name;
  }

  return $options;
}