strict-mode-via-pref-image-blocked.https.html

<!doctype html>
<html>
<head>
    <script>
        if (window.testRunner) {
            testRunner.dumpAsText();
            testRunner.overridePreference("WebKitStrictMixedContentChecking", true);
        }
    </script>
</head>
<body>
    <p>This test passes if the image below is treated as blockable content.</p>
    <img src="http://example.test:8080/security/resources/compass.jpg">
</body>
</html>

chromium/third_party/blink/web_tests/http/tests/security/mixedContent/strict-mode-via-pref-image-blocked.https.html