Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/fast/forms/checkbox/checkbox-appearance-change-by-checked.html 

<!DOCTYPE html>
<meta name=fuzzy content="maxDifference=0-3; totalPixels=0-100">

<input type=checkbox>

<script>
var checkbox = document.getElementsByTagName('input')[0];
checkbox.offsetTop;
if (window.testRunner)
    testRunner.waitUntilDone();
setTimeout(function() {
    checkbox.checked = true;
    if (window.testRunner)
        testRunner.notifyDone();
}, 0);
</script>