Get all (preg_match_all) Google docs embed iframes and wrap it with a div with PHP

wrap-google-doc-iframes.php

<?php
  preg_match_all( '@<iframe[^>]+?src="((?:https?:)?//(?:docs\.)?google\.com/([^"\'/]++)[^"\']*?)"[^>]*+>.*</iframe>@iUs', $content, $matches );
  if ( isset( $matches[0] ) && isset( $matches[0][0] ) ) {
    foreach ( $matches[0] as $googleDocIframe ) {
      $content = str_replace( $googleDocIframe, '<div class="google-doc-iframe">' . $googleDocIframe . '</div>', $content );
    }
  }