RenderLayer::isTransparent() is checking for SVG elements by doing renderer()->node()->namespaceURI() == SVGNames::svgNamespaceURI. namespaceURI() is a virtual method, and this is actually visible in profiles. I think we can replace it with an isSVGElement() bit check.
Created attachment 205672 [details] Patch
Committed r157360: <http://trac.webkit.org/changeset/157360>