CONSOLE MESSAGE: line 28: [blocked] The page at https://127.0.0.1:8443/security/mixedContent/resources/insecure-xhr-in-main-frame-window.html was not allowed to display insecure content from http://127.0.0.1:8000/.

CONSOLE MESSAGE: line 28: Not allowed to request resource
CONSOLE MESSAGE: line 28: XMLHttpRequest cannot load http://127.0.0.1:8000/ due to access control checks.
This test opens a HTTPS window that loads insecure data via XHR. We should trigger a mixed content callback because the main frame in the window is HTTPS but now has insecure data.