[Tracing] Fix inaccurate timer calculation in runtime statistics.

src/counters.cc

Index: src/counters.cc
diff --git a/src/counters.cc b/src/counters.cc
index 8fcfd541411d433911bf2003d4ce46d8535ff873..f57d88dba71fc44fd0729a41904fb297ce22aa36 100644
--- a/src/counters.cc
+++ b/src/counters.cc
@@ -368,6 +368,9 @@ void RuntimeCallStats::Reset() {
 }
 
 void RuntimeCallStats::Dump(v8::tracing::TracedValue* value) {
+  if (current_timer_ != NULL) {
+    current_timer_->Elapsed();
+  }

[Camillo Bruni, 2016/10/27 09:00:58]

Can you add the same call to RuntimeCallStats::Print() which suffers from the
same issue. 

This probably didn't matter so much since we only miss on some marginal values
from the few timers that are active once we actually print the runtime stats.

[lpy, 2016/10/27 16:59:21]

Done.

 #define DUMP_COUNTER(name) \
   if (this->name.count > 0) this->name.Dump(value);
   FOR_EACH_MANUAL_COUNTER(DUMP_COUNTER)