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

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

Index: third_party/WebKit/Source/core/probe/CoreProbes.cpp
diff --git a/third_party/WebKit/Source/core/probe/CoreProbes.cpp b/third_party/WebKit/Source/core/probe/CoreProbes.cpp
index fb0477cea5b03593ae1caa19cb1de556f4263c9d..14e943b712a8a8c4b7ab44eea2ec38b6e52d4155 100644
--- a/third_party/WebKit/Source/core/probe/CoreProbes.cpp
+++ b/third_party/WebKit/Source/core/probe/CoreProbes.cpp
@@ -52,7 +52,8 @@ 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) {
@@ -64,8 +65,13 @@ AsyncTask::AsyncTask(ExecutionContext* context,
     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() {