MozReview-Commit-ID: 328ETwMdVnq --HG-- extra : rebase_source : e16b28d137de080f9d8495c6937e24ac16b16ab1
snprintf returns the number of bytes it would have written when it runs out of space. This patch makes sure we properly handle this unlikely event in FPSCounter. This patch also makes sure we don't print out the contents of an uninitialized buffer.