ckeditor_youtube_widget.module

<?php
/**
 * Implements hook_ckeditor_plugin().
 *
 * @return type
 */
function ckeditor_youtube_widget_ckeditor_plugin() {

  $plugins['youtube_widget'] = array(
    'name' => 'youtube_widget',
    'desc' => t('Add a youtube widget.'),
    'path' => drupal_get_path('module', 'ckeditor_youtube_widget') . '/plugins/youtube_widget/',
    'buttons' => array(
      'Youtube_widget' => array('label' => 'Youtube widget', 'icon' => 'icons/youtube_widget.png'),
    )
  );

  return $plugins;
}