Named property confusion with __proto__

Named property confusion with __proto__
https://bugs.webkit.org/show_bug.cgi?id=68221

Reviewed by Eric Seidel.

Source/WebCore:

The __proto__ property is super magical because it's not a real named
property and it has higher precedence than even interceptors.  This
confuses this check, which is meant to detech which names will get
handled by our interceptor.

Test: http/tests/security/window-named-proto.html

* bindings/v8/custom/V8DOMWindowCustom.cpp:
(WebCore::V8DOMWindow::namedSecurityCheck):

LayoutTests:

* http/tests/security/resources/innocent-victim-with-iframe.html: Added.
* http/tests/security/window-named-proto-expected.txt: Added.
* http/tests/security/window-named-proto.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@95488 268f45cc-cd09-0410-ab3c-d52691b4dbfc