chromium/third_party/blink/perf_tests/bindings/document-implementation.html

<!DOCTYPE html>
<html>
<body>
<script src="../resources/runner.js"></script>
<script>
PerfTestRunner.measureRunsPerSecond({
    description: "This benchmark repeatedly accesses document.implementation.",
    run: function() {
        for (var i = 0; i < 100000; ++i)
            document.implementation;
}});
</script>
</body>
</html>