[BlackBerry] DOMSupport::isFixedPositionOrHasFixedPositionAncestor stops traversing render tree when it hits an iframe element
https://bugs.webkit.org/show_bug.cgi?id=113944

Patch by Andrew Lo <anlo@rim.com> on 2013-04-04
Reviewed by Rob Buis.
Internally reviewed by Mike Fenton.

Internal PR 320732.
When checking whether a RenderObject is fixed position or has a fixed position
ancestor, we traverse the render tree upwards.

When we reach the root of the tree, check whether the root is an
iframe and has an element owner. If so, we also need to continue iterating
up the tree from the owner to see if the iframe is a descendant of a fixed
position element.

* WebKitSupport/DOMSupport.cpp:
(BlackBerry::WebKit::DOMSupport::isFixedPositionOrHasFixedPositionAncestor):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147701 268f45cc-cd09-0410-ab3c-d52691b4dbfc