Add custom link to the contextual links of block in Drupal 7.

ccl_block.module

<?php

function ccl_block_contextual_links_view_alter(&$element, &$items) {
  if (isset($element['#element']['#block']) && $element['#element']['#block']->delta == "custom_module") {
        $element['#links']['edit_f_block'] = array(
          'title' => 'Change Content',
          'href' => url('admin/config/front/block', array('absolute' => TRUE)),
        );
    }
  }
  
?>