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

third_party/WebKit/Source/core/inspector/ThreadDebugger.h

Index: third_party/WebKit/Source/core/inspector/ThreadDebugger.h
diff --git a/third_party/WebKit/Source/core/inspector/ThreadDebugger.h b/third_party/WebKit/Source/core/inspector/ThreadDebugger.h
index 7b1cf23a985a0b9dc240544697736bbac9765cc4..1d0dd7ce07e01cb2004ae6ad8515764bf7c9764e 100644
--- a/third_party/WebKit/Source/core/inspector/ThreadDebugger.h
+++ b/third_party/WebKit/Source/core/inspector/ThreadDebugger.h
@@ -45,6 +45,7 @@ class CORE_EXPORT ThreadDebugger : public v8_inspector::V8InspectorClient,
   void AllAsyncTasksCanceled();
   void AsyncTaskStarted(void* task);
   void AsyncTaskFinished(void* task);
+  bool IsRunningAsyncTask() const { return current_async_tasks_; }
   unsigned PromiseRejected(v8::Local<v8::Context>,
                            const String& error_message,
                            v8::Local<v8::Value> exception,
@@ -110,6 +111,8 @@ class CORE_EXPORT ThreadDebugger : public v8_inspector::V8InspectorClient,
   Vector<v8_inspector::V8InspectorClient::TimerCallback> timer_callbacks_;
   Vector<void*> timer_data_;
   std::unique_ptr<UserGestureIndicator> user_gesture_indicator_;
+
+  int current_async_tasks_ = 0;
 };
 
 }  // namespace blink