This is a useful stepping stone towards reversing argument order.
Created attachment 57581 [details] The patch
Comment on attachment 57581 [details] The patch r=me, though I think it would be better if CallArguments were a class instead of a struct.
I assume this was landed? webkit-patch mark-bug-fixed will close bugs for you (and update them with links) even if you land w/o using webkit-patch.
Please re-open if I'm wrong.