The switch of ImageData to reference a Uint8ClampedArray rather than a CanvasPixelArray has caused fast/dom/Window/window-postmessage-clone.html to start failing on Mac. The reason appears to be that a couple of TypeErrors that were previously logged to the console (presumably because CanvasPixelArray wasn't cloneable) are now missing in the actual results.
Created attachment 138611 [details] Patch
Committed r115088: <http://trac.webkit.org/changeset/115088>