[Tracing] Use TracingCategoryObserver in runtime statistics

src/tracing/trace-event.h

Index: src/tracing/trace-event.h
diff --git a/src/tracing/trace-event.h b/src/tracing/trace-event.h
index 1cad33e0fc4a30f89e32508658b059d12b023352..a228608f1b702218dfa1040c615d720e8cf6929a 100644
--- a/src/tracing/trace-event.h
+++ b/src/tracing/trace-event.h
@@ -249,20 +249,10 @@ enum CategoryGroupEnabledFlags {
   INTERNAL_TRACE_EVENT_UID(ScopedContext)                                  \
   INTERNAL_TRACE_EVENT_UID(scoped_context)(context);
 
-#define TRACE_EVENT_RUNTIME_CALL_STATS_TRACING_ENABLED() \
-  base::NoBarrier_Load(&v8::internal::tracing::kRuntimeCallStatsTracingEnabled)
-
 #define TRACE_EVENT_CALL_STATS_SCOPED(isolate, category_group, name) \
   INTERNAL_TRACE_EVENT_CALL_STATS_SCOPED(isolate, category_group, name)
 
 #define INTERNAL_TRACE_EVENT_CALL_STATS_SCOPED(isolate, category_group, name)  \
-  {                                                                            \
-    INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(                                    \
-        TRACE_DISABLED_BY_DEFAULT("v8.runtime_stats"));                        \
-    base::NoBarrier_Store(                                                     \
-        &v8::internal::tracing::kRuntimeCallStatsTracingEnabled,               \
-        INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE());     \
-  }                                                                            \
   INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group);                      \
   v8::internal::tracing::CallStatsScopedTracer INTERNAL_TRACE_EVENT_UID(       \
       tracer);                                                                 \