Both http-auth-private-mode-changed.html and http-auth-private-mode-changed.php must be served over http.
This tests the behavior of http authentication when private browsering is set from on to off. This is for https://bugs.webkit.org/show_bug.cgi?id=84697
      Test steps:
      1. Set Private Browsing on. (Settings -> Privacy & Security -> Private Browsing).
      2. Press Start test here.
      3. When dialog pops up, enter real credential(username: "aaaa", password: "aaaa") and press Ok button.
      4. Set Private Browsing off. (Settings -> Privacy & Security -> Private Browsing).
      5. Refresh the page.
      6. There should be a dialog for you to input username and password again.
         If you can't see the dialog, this test fails.