Fix lighting filters on Windows, and re-enable the GPU path.
Fix lighting filters on Windows, and re-enable the GPU path.

Review URL:  http://codereview.appspot.com/6354094/



git-svn-id: e8541e15acce502a64c929015570ad1648e548cd@4557 2bbb7eff-a529-9590-31e7-b0007b416f81

mrobinson/skia,mrobinson/skia,Cue/skia,mrobinson/skia,mrobinson/skia,metajack/skia,Cue/skia,metajack/skia,mrobinson/skia,Cue/skia,metajack/skia,metajack/skia,Cue/skia