CONSOLE WARNING: line 4: Mixed Content: The page at 'https://127.0.0.1:8443/security/mixedContent/resources/frame-with-insecure-css.html' was loaded over HTTPS, but requested an insecure stylesheet 'http://example.test:8080/security/mixedContent/resources/style.css'. This content should also be served over HTTPS.
This test opens a window that loads an insecure style sheet. We should trigger a mixed content callback because the main frame in the window is HTTPS but is running insecure content.