Bug 1062709 (part 1, attempt 2) - Add a frame number argument to NS_WalkStackCallback. r=dbaron.

--HG--
extra : rebase_source : 4f7060a9ae0bed180899651c50e8ea8857e72d63
Bug 1062709 (part 2, attempt 2) - Clean up stack printing and fixing. r=dbaron.

--HG--
extra : rebase_source : 626fd23a14ec90cfc9807c3d555169ec6463d19d