Bug 962325 - Add filename to profiler I/O markers. r=bgirard

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extra : rebase_source : 6ec4d08834f57946681b65064c1e5764572d28e7
Bug 970494 - Markers should be time based and not sample based. r=bgirard

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extra : rebase_source : c1e3e77fa8f7ad2c5eec7f092d96bf3719db3a8c