Bug 837271 - part 1 - add means to control computation of extended statistics to histogram code; r=vladan; a=lsblakk
Bug 837271 - part 2 - add extended_statistics_ok mechanism to histogram machinery; r=vladan; a=lsblakk
Bug 837271 - part 3 - flag histograms as OK for extended statistics computation in Histograms.json; r=vladan; a=lsblakk
Bug 837271 - part 4 - add test for extended statistics not being recorded; r=taras; a=lsblakk