Implement Location.ancestorOrigins

Implement Location.ancestorOrigins
https://bugs.webkit.org/show_bug.cgi?id=83493

Reviewed by David Levin.

Source/WebCore:

Test: fast/dom/Window/Location/ancestor-origins.html

This patch implements Location.ancestorOrigins(), which returns a list
of the origins of the enclosing frames.  This API has been discussed
both on webkit-dev (see discussion following
https://lists.webkit.org/pipermail/webkit-dev/2012-March/020090.html)
and on the whatwg list (see discussion following
http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2012-March/035188.html).

* page/Location.cpp:
(WebCore::Location::ancestorOrigins):
(WebCore):
* page/Location.h:
(Location):
* page/Location.idl:

LayoutTests:

* fast/dom/Window/Location/ancestor-origins-expected.txt: Added.
* fast/dom/Window/Location/ancestor-origins.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@113945 268f45cc-cd09-0410-ab3c-d52691b4dbfc