Implement AggregatableHistogramTimer and use it to measure how much time

src/counters.cc

Index: src/counters.cc
diff --git a/src/counters.cc b/src/counters.cc
index 972bd6862c0f5a5524dfd9f57021e9eb4b61c1a8..ec5d21d47c3a415846f9e5c5c7537ddf04972d82 100644
--- a/src/counters.cc
+++ b/src/counters.cc
@@ -66,6 +66,11 @@ Counters::Counters(Isolate* isolate) {
     HISTOGRAM_TIMER_LIST(HT)
 #undef HT
 
+#define AHT(name, caption) \
+  name##_ = AggregatableHistogramTimer(#caption, 0, 10000, 50, isolate);
+    AGGREGATABLE_HISTOGRAM_TIMER_LIST(AHT)
+#undef AHT
+
 #define HP(name, caption) \
     name##_ = Histogram(#caption, 0, 101, 100, isolate);
     HISTOGRAM_PERCENTAGE_LIST(HP)
@@ -156,6 +161,10 @@ void Counters::ResetHistograms() {
     HISTOGRAM_TIMER_LIST(HT)
 #undef HT
 
+#define AHT(name, caption) name##_.Reset();
+    AGGREGATABLE_HISTOGRAM_TIMER_LIST(AHT)
+#undef AHT
+
 #define HP(name, caption) name##_.Reset();
     HISTOGRAM_PERCENTAGE_LIST(HP)
 #undef HP