[counters] adding runtime call timers for GC

src/heap/gc-tracer.cc

Index: src/heap/gc-tracer.cc
diff --git a/src/heap/gc-tracer.cc b/src/heap/gc-tracer.cc
index 4d02fdeff57071ef61ec73ca3feb90653ca27eb2..5166b6e62be6da6bfe56caa72a360ec287fac02c 100644
--- a/src/heap/gc-tracer.cc
+++ b/src/heap/gc-tracer.cc
@@ -24,6 +24,13 @@ static intptr_t CountTotalHolesSize(Heap* heap) {
 GCTracer::Scope::Scope(GCTracer* tracer, ScopeId scope)
     : tracer_(tracer), scope_(scope) {
   start_time_ = tracer_->heap_->MonotonicallyIncreasingTimeInMs();
+  // TODO(cbruni): remove once we fully moved to a trace-based system.
+  if (FLAG_runtime_call_stats) {
+    RuntimeCallStats* stats =
+        tracer_->heap_->isolate()->counters()->runtime_call_stats();
+    timer_.Initialize(&stats->GC, stats->current_timer());
+    stats->Enter(&timer_);
+  }
 }
 
 
@@ -31,6 +38,10 @@ GCTracer::Scope::~Scope() {
   DCHECK(scope_ < NUMBER_OF_SCOPES);  // scope_ is unsigned.
   tracer_->current_.scopes[scope_] +=
       tracer_->heap_->MonotonicallyIncreasingTimeInMs() - start_time_;
+  // TODO(cbruni): remove once we fully moved to a trace-based system.
+  if (FLAG_runtime_call_stats) {
+    tracer_->heap_->isolate()->counters()->runtime_call_stats()->Leave(&timer_);
+  }
 }