LayoutTests/http/tests/resourceLoadStatistics/set-custom-prevalent-resource-in-debug-mode.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <script src="/js-test-resources/js-test.js"></script>
    <script src="resources/util.js"></script>
</head>
<body>
<script>
    description("Test for enabling debug mode and that it allows setting a custom domain as a prevalent resource.");
    jsTestIsAsync = true;

    const thirdPartyOrigin = "http://localhost:8000";

    if (window.testRunner && window.internals) {
        setEnableFeature(true, function() {
            if (testRunner.isStatisticsPrevalentResource(thirdPartyOrigin))
                testFailed(thirdPartyOrigin + " already set as prevalent resource.");

            testRunner.setStatisticsPrevalentResourceForDebugMode(thirdPartyOrigin, function() {
                testRunner.setStatisticsDebugMode(true, function() {
                    if (!testRunner.isStatisticsPrevalentResource(thirdPartyOrigin))
                        testFailed(thirdPartyOrigin + " didn't get set as prevalent resource.");
                    else
                        testPassed(thirdPartyOrigin + " got set as a custom prevalent resource in debug mode.");
                    testRunner.setStatisticsDebugMode(false, function() {
                        setEnableFeature(false, finishJSTest);
                    });
                });
            });
        });
    }
</script>
</body>
</html>