diff --git a/core/lib/Drupal/Component/Diff/DiffEngine.php b/core/lib/Drupal/Component/Diff/DiffEngine.php
index 5be8a9d..7f95d2c 100644
--- a/core/lib/Drupal/Component/Diff/DiffEngine.php
+++ b/core/lib/Drupal/Component/Diff/DiffEngine.php
@@ -1229,7 +1229,7 @@ function _changed($orig, $closing) {
  * @private
  * @subpackage DifferenceEngine
  */
-class DrupalDiffInline {
+abstract class DrupalDiffInline {
   var $a;
   var $b;
 
@@ -1243,55 +1243,11 @@ function __construct($a, $b) {
 
   /**
    * Render differences inline using HTML markup.
+   *
+   * @return string
+   *   Returns the rendered output of the HTML markup.
    */
-  function render() {
-    $a = preg_split('/(<[^>]+?>| )/', $this->a, -1, PREG_SPLIT_DELIM_CAPTURE);
-    $b = preg_split('/(<[^>]+?>| )/', $this->b, -1, PREG_SPLIT_DELIM_CAPTURE);
-    $diff = new Diff($a, $b);
-    $diff->edits = $this->process_edits($diff->edits);
-
-    // Assemble highlighted output
-    $output = '';
-    foreach ($diff->edits as $chunk) {
-      switch ($chunk->type) {
-        case 'copy':
-          $output .= implode('', $chunk->closing);
-          break;
-        case 'delete':
-          foreach ($chunk->orig as $i => $piece) {
-            if (strpos($piece, '<') === 0 && Unicode::substr($piece, Unicode::strlen($piece) - 1) === '>') {
-              $output .= $piece;
-            }
-            else {
-              $diff_inline_chunk = array(
-                '#theme' => 'diff_inline_chunk',
-                '#text' => $piece,
-                '#type' => $chunk->type,
-              );
-              $output .= drupal_render($diff_inline_chunk);
-            }
-          }
-          break;
-        default:
-          $chunk->closing = $this->process_chunk($chunk->closing);
-          foreach ($chunk->closing as $i => $piece) {
-            if ($piece === ' ' || (strpos($piece, '<') === 0 && Unicode::substr($piece, Unicode::strlen($piece) - 1) === '>' && Unicode::strtolower(Unicode::substr($piece, 1, 3)) != 'img')) {
-              $output .= $piece;
-            }
-            else {
-              $diff_inline_chunk = array(
-                '#theme' => 'diff_inline_chunk',
-                '#text' => $piece,
-                '#type' => $chunk->type,
-              );
-              $output .= drupal_render($diff_inline_chunk);
-            }
-          }
-          break;
-      }
-    }
-    return $output;
-  }
+  abstract public function render();
 
   /**
    * Merge chunk segments between tag delimiters.