"flat_key","key","int_value","string_value"
"chrome_histogram_sample.name","chrome_histogram_sample.name","[NULL]","Compositing.Display.DrawToSwapUs"
"chrome_histogram_sample.name","chrome_histogram_sample.name","[NULL]","CompositorLatency.TotalLatency"
"chrome_histogram_sample.name","chrome_histogram_sample.name","[NULL]","Graphics.Smoothness.Checkerboarding.MainThreadAnimation"
"chrome_histogram_sample.name","chrome_histogram_sample.name","[NULL]","Memory.GPU.PeakMemoryUsage.PageLoad"
"chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",10,"[NULL]"
"chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",20,"[NULL]"
"chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",30,"[NULL]"
"chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",40,"[NULL]"
"chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",50,"[NULL]"
"chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",60,"[NULL]"
"chrome_histogram_sample.name_iid","chrome_histogram_sample.name_iid",1,"[NULL]"
"chrome_histogram_sample.name_iid","chrome_histogram_sample.name_iid",2,"[NULL]"
"chrome_histogram_sample.name_iid","chrome_histogram_sample.name_iid",3,"[NULL]"
"chrome_histogram_sample.name_iid","chrome_histogram_sample.name_iid",4,"[NULL]"
"chrome_histogram_sample.sample","chrome_histogram_sample.sample",100,"[NULL]"
"chrome_histogram_sample.sample","chrome_histogram_sample.sample",200,"[NULL]"
"chrome_histogram_sample.sample","chrome_histogram_sample.sample",300,"[NULL]"
"chrome_histogram_sample.sample","chrome_histogram_sample.sample",400,"[NULL]"
"chrome_histogram_sample.sample","chrome_histogram_sample.sample",500,"[NULL]"
"chrome_histogram_sample.sample","chrome_histogram_sample.sample",600,"[NULL]"
"event.category","event.category","[NULL]","disabled-by-default-histogram_samples"
"event.name","event.name","[NULL]","[NULL]"
"is_root_in_scope","is_root_in_scope",1,"[NULL]"
"source","source","[NULL]","descriptor"
"source_id","source_id",0,"[NULL]"