document.referrer leakage with XSS Auditor page block
https://bugs.webkit.org/show_bug.cgi?id=109089

Reviewed by Adam Barth.

Source/WebCore:

Pass "about:blank" as referrer instead of "" so that the actual page
is not leaked when empty referrers are replaced later on in the
request.

* html/parser/XSSAuditorDelegate.cpp:
(WebCore::XSSAuditorDelegate::didBlockScript):

LayoutTests:

Test prints the referrer to show it isn't leaked.

* http/tests/security/xssAuditor/full-block-script-tag-expected.txt:
* http/tests/security/xssAuditor/full-block-script-tag.html:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142063 268f45cc-cd09-0410-ab3c-d52691b4dbfc