SVGRenderStyle(Defs) is old legacy code and needs to be cleaned up. While I'm at it, we could save memory be joining StyleMaskData/StyleClipData in a single StyleResourceData. For consistency StyleMarkerData will be named StyleInheritedResourceData. All naming schemes should be unified for clipper / masker / marker / filter, see the upcoming patch.
Created attachment 53323 [details] Patch
Attachment 53323 [details] did not build on chromium: Build output: http://webkit-commit-queue.appspot.com/results/1602462
Attachment 53323 [details] did not build on gtk: Build output: http://webkit-commit-queue.appspot.com/results/1671314
Created attachment 53325 [details] Patch
Updated patch against trunk, was missing RenderSVGResourceClipper changes after Dirks commit.
Comment on attachment 53325 [details] Patch LGTM r=me
Committed r57575: <http://trac.webkit.org/changeset/57575>