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

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extra : rebase_source : 0f9b2d6310433ed56f5552706fcf2a96571aee25
Bug 1062709 (part 2) - Clean up stack printing and fixing. r=dbaron.

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extra : rebase_source : 18158d4474cb8826813a3866eba57b710e14db99