[DevTools] added creation stack for event listeners without scheduled stack

third_party/WebKit/Source/core/probe/CoreProbes.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 34 matching lines @@
 #include "core/workers/WorkerGlobalScope.h"
 #include "platform/instrumentation/tracing/TraceEvent.h"
 #include "platform/loader/fetch/FetchInitiatorInfo.h"
 
 namespace blink {
 namespace probe {
 
 AsyncTask::AsyncTask(ExecutionContext* context,
                      void* task,
                      const char* step,
-                     bool enabled)
+                     bool enabled,
+                     bool optional)
     : debugger_(enabled ? ThreadDebugger::From(ToIsolate(context)) : nullptr),
       task_(task),
       recurring_(step) {
   if (recurring_) {
     TRACE_EVENT_FLOW_STEP0("devtools.timeline.async", "AsyncTask",
                            TRACE_ID_LOCAL(reinterpret_cast<uintptr_t>(task)),
                            step ? step : "");
   } else {
     TRACE_EVENT_FLOW_END0("devtools.timeline.async", "AsyncTask",
                           TRACE_ID_LOCAL(reinterpret_cast<uintptr_t>(task)));
   }
-  if (debugger_)
+  if (debugger_) {
+    if (optional && debugger_->IsRunningAsyncTask()) {

[dgozman, 2017/05/10 18:36:30]

Instead of calling this, pass optional to AsyncTaskStarted.

[kozy, 2017/05/10 21:24:01]

Done.

+      debugger_ = nullptr;
+      return;
+    }
     debugger_->AsyncTaskStarted(task_);
+  }
 }
 
 AsyncTask::~AsyncTask() {
   if (debugger_) {
     debugger_->AsyncTaskFinished(task_);
     if (!recurring_)
       debugger_->AsyncTaskCanceled(task_);
   }
 }
 
@@ skipping 52 matching lines @@
 void ContinueWithPolicyIgnore(LocalFrame* frame,
                               DocumentLoader* loader,
                               unsigned long identifier,
                               const ResourceResponse& r,
                               Resource* resource) {
   DidReceiveResourceResponseButCanceled(frame, loader, identifier, r, resource);
 }
 
 }  // namespace probe
 }  // namespace blink