[Tracing] Fix runtime call stats tracing for GC.

src/counters-inl.h

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COUNTERS_INL_H_
 #define V8_COUNTERS_INL_H_
 
 #include "src/counters.h"
 
 namespace v8 {
 namespace internal {
 
 RuntimeCallTimerScope::RuntimeCallTimerScope(
     HeapObject* heap_object, RuntimeCallStats::CounterId counter_id) {
-  if (V8_UNLIKELY(FLAG_runtime_call_stats)) {
+  if (V8_UNLIKELY(TRACE_EVENT_RUNTIME_CALL_STATS_TRACING_ENABLED())) {
+    isolate_ = heap_object->GetIsolate();
+    is_tracing_ = true;
+    RuntimeCallStats::Enter(isolate_->counters()->tracing_runtime_call_stats(),
+                            &timer_, counter_id);
+  } else if (V8_UNLIKELY(FLAG_runtime_call_stats)) {
     isolate_ = heap_object->GetIsolate();
     RuntimeCallStats::Enter(isolate_->counters()->runtime_call_stats(), &timer_,
                             counter_id);
   }
-  // TODO(lpy): Add a tracing equivalent for the runtime call stats.
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COUNTERS_INL_H_