public function diffOriginals()
 {
     $engine = new PhabricatorDifferenceEngine();
     $changeset = $engine->generateChangesetFromFileContent(implode('', mpull($this->originalLeft->getHunks(), 'getChanges')), implode('', mpull($this->originalRight->getHunks(), 'getChanges')));
     $parser = new DifferentialHunkParser();
     return $parser->parseHunksForHighlightMasks($changeset->getHunks(), $this->originalLeft->getHunks(), $this->originalRight->getHunks());
 }