WebView.blockedContent indicates the wrong state in some circumstances

[Chris Coulson]

Whilst writing the test for this, I noticed that if you do the following:

- set WebPreferences.canDisplayInsecureContent to false
- load a page over SSL that contains an insecure script and an insecure image (at this point, the ContentTypeMixedDisplay and ContentTypeMixedScript bits of WebView.blockedContent are set, correctly)
- call WebView.setCanTemporarilyDisplayInsecureContent(true) (which causes the page to reload).

At this point, WebView.blockedContent should still have the ContentTypeMixedScript bit set, but it is now clear