Move and rename TaskTimeTracker to public interface exposed to WebThread, use in WebPerf Agent.

third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc b/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
index 208a68019125559268769e1588b9a6882f050d5a..24a6da91d98d2d72e1527f869c5e5b81686defb4 100644
--- a/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
@@ -1411,15 +1411,19 @@ void RendererSchedulerImpl::ReportTaskTime(base::TimeTicks start_time,
                                            base::TimeTicks end_time) {
   MainThreadOnly().queueing_time_estimator.OnToplevelTaskCompleted(start_time,
                                                                    end_time);
-  MainThreadOnly().long_task_tracker.RecordLongTask(
-      start_time, end_time - start_time);
   UMA_HISTOGRAM_CUSTOM_COUNTS("RendererScheduler.TaskTime",
                               (end_time - start_time).InMicroseconds(), 1,
                               1000000, 50);
 }
 
-LongTaskTracker::LongTaskTiming RendererSchedulerImpl::GetLongTaskTiming() {
-  return MainThreadOnly().long_task_tracker.GetLongTaskTiming();
+void RendererSchedulerImpl::AddTaskTimeObserver(
+    WebThread::TaskTimeObserver* task_time_observer) {
+    helper_.AddTaskTimeObserver(task_time_observer);
+}
+
+void RendererSchedulerImpl::RemoveTaskTimeObserver(
+    WebThread::TaskTimeObserver* task_time_observer) {
+    helper_.RemoveTaskTimeObserver(task_time_observer);
 }
 
 void RendererSchedulerImpl::OnQueueingTimeForWindowEstimated(