core/app/Http/Controllers/Admin/History.php

<?php
namespace App\Http\Controllers\Admin;

use App\Models\Content;
use App\Models\ContentHistory;

class History extends Controller
{
    /**
     * @var ContentHistory
     */
    private $history;

    public function __construct(ContentHistory $history)
    {
        parent::__construct();
        $this->history = $history;
    }

    /**
     * @param $id
     *
     * @return \Illuminate\Contracts\View\Factory|\Illuminate\View\View
     */
    public function getOverview($id)
    {
        // test if given content id is static page and if exists
        $content = Content::findOrFail($id);

        $history = $this->history->getStructuredHistoryOf($content);

        return view('admin/history.overview', [
            'history' => $history,
            'page'    => $content
        ]);
    }

    public function getDiff($revision, $id)
    {
        $change = $this->history->findOrFail($id);
        $diff = $this->history->getDiff($change);

        return view('admin/history.diff', [
            'change'     => $change,
            'columnName' => 'Page content',
            'diff'       => $diff
        ]);
    }
}