Fix use of history timers in background threads.

src/counters.cc

Index: src/counters.cc
diff --git a/src/counters.cc b/src/counters.cc
index ff76aa650a8b6cfd3911ba390c3772a7c82ceaeb..a06c91f3f7ed554ab2b545fbf8dc09e86daf3b1f 100644
--- a/src/counters.cc
+++ b/src/counters.cc
@@ -77,27 +77,23 @@ void* Histogram::CreateHistogram() const {
   return counters_->CreateHistogram(name_, min_, max_, num_buckets_);
 }
 
-
-// Start the timer.
-void HistogramTimer::Start() {
-  if (Enabled()) {
-    timer_.Start();
-  }
-  Logger::CallEventLogger(counters()->isolate(), name(), Logger::START, true);
+void TimedHistogram::Start(base::ElapsedTimer* timer, Isolate* isolate) {
+  if (Enabled()) timer->Start();
+  if (isolate) Logger::CallEventLogger(isolate, name(), Logger::START, true);
 }
 
-
-// Stop the timer and record the results.
-void HistogramTimer::Stop() {
+void TimedHistogram::Stop(base::ElapsedTimer* timer, Isolate* isolate) {
   if (Enabled()) {
-    int64_t sample = resolution_ == MICROSECOND
-                         ? timer_.Elapsed().InMicroseconds()
-                         : timer_.Elapsed().InMilliseconds();
     // Compute the delta between start and stop, in microseconds.
+    int64_t sample = resolution_ == HistogramTimerResolution::MICROSECOND
+                         ? timer->Elapsed().InMicroseconds()
+                         : timer->Elapsed().InMilliseconds();
+    timer->Stop();
     AddSample(static_cast<int>(sample));
-    timer_.Stop();
   }
-  Logger::CallEventLogger(counters()->isolate(), name(), Logger::END, true);
+  if (isolate != nullptr) {
+    Logger::CallEventLogger(isolate, name(), Logger::END, true);
+  }
 }
 
 Counters::Counters(Isolate* isolate)
@@ -127,20 +123,38 @@ Counters::Counters(Isolate* isolate)
                   histogram.num_buckets, this);
   }
 
+  const int DefaultTimedHistogramNumBuckets = 50;
+
   static const struct {
     HistogramTimer Counters::*member;
     const char* caption;
     int max;
-    HistogramTimer::Resolution res;
+    HistogramTimerResolution res;
   } kHistogramTimers[] = {
 #define HT(name, caption, max, res) \
-  {&Counters::name##_, #caption, max, HistogramTimer::res},
+  {&Counters::name##_, #caption, max, HistogramTimerResolution::res},
       HISTOGRAM_TIMER_LIST(HT)
 #undef HT
   };
   for (const auto& timer : kHistogramTimers) {
-    this->*timer.member =
-        HistogramTimer(timer.caption, 0, timer.max, timer.res, 50, this);
+    this->*timer.member = HistogramTimer(timer.caption, 0, timer.max, timer.res,
+                                         DefaultTimedHistogramNumBuckets, this);
+  }
+
+  static const struct {
+    TimedHistogram Counters::*member;
+    const char* caption;
+    int max;
+    HistogramTimerResolution res;
+  } kTimedHistograms[] = {
+#define HT(name, caption, max, res) \
+  {&Counters::name##_, #caption, max, HistogramTimerResolution::res},
+      TIMED_HISTOGRAM_LIST(HT)
+#undef HT
+  };
+  for (const auto& timer : kTimedHistograms) {
+    this->*timer.member = TimedHistogram(timer.caption, 0, timer.max, timer.res,
+                                         DefaultTimedHistogramNumBuckets, this);
   }
 
   static const struct {
@@ -152,8 +166,8 @@ Counters::Counters(Isolate* isolate)
 #undef AHT
   };
   for (const auto& aht : kAggregatableHistogramTimers) {
-    this->*aht.member =
-        AggregatableHistogramTimer(aht.caption, 0, 10000000, 50, this);
+    this->*aht.member = AggregatableHistogramTimer(
+        aht.caption, 0, 10000000, DefaultTimedHistogramNumBuckets, this);
   }
 
   static const struct {
@@ -294,6 +308,10 @@ void Counters::ResetCreateHistogramFunction(CreateHistogramCallback f) {
     HISTOGRAM_TIMER_LIST(HT)
 #undef HT
 
+#define HT(name, caption, max, res) name##_.Reset();
+    TIMED_HISTOGRAM_LIST(HT)
+#undef HT
+
 #define AHT(name, caption) name##_.Reset();
     AGGREGATABLE_HISTOGRAM_TIMER_LIST(AHT)
 #undef AHT