[Tracing] Use TracingCategoryObserver in runtime statistics

src/tracing/tracing-category-observer.cc

Index: src/tracing/tracing-category-observer.cc
diff --git a/src/tracing/tracing-category-observer.cc b/src/tracing/tracing-category-observer.cc
index f9315b4ce456beb5d55b0b02c6ca06d00e6b006e..f9ebada248db235914024abbffd1e68cb71f469d 100644
--- a/src/tracing/tracing-category-observer.cc
+++ b/src/tracing/tracing-category-observer.cc
@@ -17,7 +17,9 @@ std::unique_ptr<TracingCategoryObserver> TracingCategoryObserver::Create() {
       new TracingCategoryObserverImpl());
 }
 
-TracingCategoryObserverImpl::TracingCategoryObserverImpl() {}
+TracingCategoryObserverImpl::TracingCategoryObserverImpl() {
+  TRACE_EVENT_WARMUP_CATEGORY(TRACE_DISABLED_BY_DEFAULT("v8.runtime_stats"));
+}
 
 TracingCategoryObserverImpl::~TracingCategoryObserverImpl() {
   OnTraceDisabled();