CTTE: RenderScrollbar DOM owner is always an Element.
Created attachment 213399 [details] Patch
Created attachment 213400 [details] Patch
Created attachment 213401 [details] To land
Comment on attachment 213401 [details] To land Attachment 213401 [details] did not pass win-ews (win): Output: http://webkit-queues.appspot.com/results/3314016
Committed r156942: <http://trac.webkit.org/changeset/156942>