Ensure runtime call stats show up for microtasks

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 174913ffb8b8571153b1016c3d9a570212535877..036841a9403ea094de9ec5651718ef9b93ff8865 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -3316,6 +3316,7 @@ void Isolate::RunMicrotasks() {
 void Isolate::RunMicrotasksInternal() {
   if (!pending_microtask_count()) return;
   TRACE_EVENT0("v8.execute", "RunMicrotasks");
+  TRACE_EVENT_CALL_STATS_SCOPED(this, "v8", "V8.RunMicrotasks");

[lpy, 2016/12/22 00:38:46]

What if we remove TRACE_EVENT0 and use "v8.execute" here?

[jgruber, 2016/12/22 09:33:28]

Removed TRACE_EVENT0, but using "v8.execute" as the category breaks the display
in chrome://tracing so I kept "v8".

   while (pending_microtask_count() > 0) {
     HandleScope scope(this);
     int num_tasks = pending_microtask_count();