We need to transform the image when painting it, so we need to fall out of the optimization. We could do some complicated things to keep the optimization in this case, but it's not a super critical case and the simple image layer optimization is relatively new. <rdar://problem/14071174>
Conveniently the layer is already the right size/shape, so we really just need to tell RenderLayerBacking to do the right thing.
Created attachment 208231 [details] patch
Created attachment 208233 [details] patch
http://trac.webkit.org/changeset/153797
Wouldn't a ref-test be nicer here?
(In reply to comment #5) > Wouldn't a ref-test be nicer here? Yes; I just borrowed the existing image-orientation test and made it composited, though.