We force the URL bar to show for broken HTTPS.
This means that fullscreen is disabled, and scrolling the page does not hide the URL bar.

We should consider applying this to:
1) HTTP pages with password and/or credit card forms ( Issue 647754 )
2) HTTPS pages with mixed content.
3) All HTTP pages.

In the first two cases, the URL bar may be hidden when the relevant content is added to the page, meaning that even a savvy user would not see the warning if we don't make the URL bar appear.