Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/fast/dom/Window/window-constructor.html 

<!DOCTYPE html>
<script src="../../../resources/testharness.js"></script>
<script src="../../../resources/testharnessreport.js"></script>
<script>
test(() => {
  assert_equals(window.constructor.prototype, window.__proto__,
      "Window constructor prototype is window prototype.");

  assert_throws_js(TypeError, () => { window.constructor(); },
      "Window constructor must be non-callable.");
  assert_throws_js(TypeError, () => { new window.constructor; },
      "Window constructor must be non-callable.");

  assert_throws_js(TypeError, () => { window.__proto__.constructor(); },
      "Window.prototype constructor must be non-callable.");
  assert_throws_js(TypeError, () => { new window.__proto__.constructor; },
      "Window.prototype constructor must be non-callable.");

  assert_equals(window.__proto__.__proto__.constructor, EventTarget,
      "WindowProperties constructor is EventTarget.");
}, "Test Window and its prototype chain's constructors.");
</script>