POC: Instrument task time tracker

components/scheduler/child/scheduler_helper.cc

Index: components/scheduler/child/scheduler_helper.cc
diff --git a/components/scheduler/child/scheduler_helper.cc b/components/scheduler/child/scheduler_helper.cc
index 43944359e0497c0b997600f46f027efed3516ea1..609090ab43312ec9edfcadc64781a6a76afec938 100644
--- a/components/scheduler/child/scheduler_helper.cc
+++ b/components/scheduler/child/scheduler_helper.cc
@@ -18,11 +18,13 @@ SchedulerHelper::SchedulerHelper(
     const char* disabled_by_default_tracing_category,
     const char* disabled_by_default_verbose_tracing_category)
     : task_queue_manager_delegate_(task_queue_manager_delegate),
+      task_time_tracker_(new TaskTimeTracker()),
       task_queue_manager_(
           new TaskQueueManager(task_queue_manager_delegate,
                                tracing_category,
                                disabled_by_default_tracing_category,
-                               disabled_by_default_verbose_tracing_category)),
+                               disabled_by_default_verbose_tracing_category,
+                               task_time_tracker_.get())),
       control_task_runner_(NewTaskQueue(
           TaskQueue::Spec("control_tq")
               .SetWakeupPolicy(TaskQueue::WakeupPolicy::DONT_WAKE_OTHER_QUEUES)
@@ -121,7 +123,9 @@ void SchedulerHelper::SetObserver(Observer* observer) {
   CheckOnValidThread();
   observer_ = observer;
   DCHECK(task_queue_manager_);
+  DCHECK(task_time_tracker_);
   task_queue_manager_->SetObserver(this);
+  task_time_tracker_->SetObserver(this);
 }
 
 RealTimeDomain* SchedulerHelper::real_time_domain() const {
@@ -161,4 +165,10 @@ TaskQueue* SchedulerHelper::CurrentlyExecutingTaskQueue() const {
   return task_queue_manager_->currently_executing_task_queue();
 }
 
+// TaskTimeTracker::TaskTimeObserver implementation:
+void SchedulerHelper::OnLongTask(base::TimeDelta long_task_time) {
+  // Record long task
+  // will be queried from RendererSchedulerImpl in BeginMainFrame
+}
+
 }  // namespace scheduler