Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/external/wpt/css/css-color/blacksquare-ref.html 

<!DOCTYPE html>
<meta charset="utf-8">
<title>Black square reference</title>
<style>
    .test { background-color: #000000; width: 12em; height: 12em; }
</style>
<body>
    <p>Test passes if you see a black square, and no red.</p>
    <div class="test"></div>
</body>