nonwebby-scheme-in-form-warning.https.html

<!DOCTYPE html>
<html>
<body>
<p>
    This tests that forms with non-webby actions trigger a
    mixed content warning. The test passes if the console shows a mixed content warning.
</p>
<script>
if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.dumpChildFrames();
    testRunner.overridePreference("WebKitAllowRunningInsecureContent", false);
}
</script>
<form action="nonwebbyscheme://mixed-content-warning-should-appear"></form>
</body>
</html>

chromium/third_party/blink/web_tests/http/tests/security/mixedContent/nonwebby-scheme-in-form-warning.https.html