perf_hooks: test event loop delay fast api callbacks

Add test coverage for the per iteration event loop delay histogram start
and stop callbacks

Use disitinct debug tracking keys for the event loop delay histogram
callbacks.

Author: pabloerhard

src/histogram.cc

@@ -596,7 +596,7 @@ void ELDHistogram::Start(const FunctionCallbackInfo<Value>& args) {
 }
 
 void ELDHistogram::FastStart(Local<Value> receiver, bool reset) {
-  TRACK_V8_FAST_API_CALL("histogram.start");
+  TRACK_V8_FAST_API_CALL("histogram.eventLoopDelay.start");
   ELDHistogram* histogram;
   ASSIGN_OR_RETURN_UNWRAP(&histogram, receiver);
   histogram->OnStart(reset ? StartFlags::RESET : StartFlags::NONE);
@@ -609,7 +609,7 @@ void ELDHistogram::Stop(const FunctionCallbackInfo<Value>& args) {
 }
 
 void ELDHistogram::FastStop(Local<Value> receiver) {
-  TRACK_V8_FAST_API_CALL("histogram.stop");
+  TRACK_V8_FAST_API_CALL("histogram.eventLoopDelay.stop");
   ELDHistogram* histogram;
   ASSIGN_OR_RETURN_UNWRAP(&histogram, receiver);
   histogram->OnStop();

test/parallel/test-perf-hooks-monitor-event-loop-delay-fast-calls.js

@@ -0,0 +1,26 @@
+// Flags: --allow-natives-syntax --expose-internals --no-warnings
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+
+const { internalBinding } = require('internal/test/binding');
+const { createELDHistogram } = internalBinding('performance');
+
+const histogram = createELDHistogram(1, true);
+
+function testFastMethods() {
+  histogram.start(true);
+  histogram.stop();
+}
+
+eval('%PrepareFunctionForOptimization(testFastMethods)');
+testFastMethods();
+eval('%OptimizeFunctionOnNextCall(testFastMethods)');
+testFastMethods();
+
+if (common.isDebug) {
+  const { getV8FastApiCallCount } = internalBinding('debug');
+  assert.strictEqual(getV8FastApiCallCount('histogram.eventLoopDelay.start'), 1);
+  assert.strictEqual(getV8FastApiCallCount('histogram.eventLoopDelay.stop'), 1);
+}