Tighten typing in SVGResourcesCycleSolver a bit.
<https://webkit.org/b/124104>

Make the SVGResourcesCycleSolver constructor take a RenderElement&
and a SVGResources&.

While I was in the neighborhood, also converted one loop to use a
renderer iterator instead of walking siblings manually.

Finally used "auto" to clean up some overly wordy loops.

Reviewed by Anders Carlsson.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@159000 268f45cc-cd09-0410-ab3c-d52691b4dbfc