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..9abc7b7f2a4c07468b19966079f1263d0b9a4e68 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
@@ -36,6 +36,11 @@ const double kShortIdlePeriodDurationPercentile = 50;
 // Amount of idle time left in a frame (as a ratio of the vsync interval) above
 // which main thread compositing can be considered fast.
 const double kFastCompositingIdleTimeThreshold = .2;
+
+base::TimeTicks MonotonicTimeInSecondsToTimeTicks(double monotonicTimeInSeconds) {
+  return base::TimeTicks::FromInternalValue(

[alph, 2016/08/22 22:21:27]

nit: Consider the following one, as it ensures better unit agreement:
base::TimeTicks() + base::TimeDelta::FromSecondsD(monotonicTimeInSeconds)

[panicker, 2016/08/22 23:29:46]

What's the an equivalent counterpart for converting the other way around?
I want to keep the conversions here and in MonotonicTimeInSeconds in
third_party/WebKit/Source/platform/scheduler/base/task_queue_manager.cc
to be consistent with each other.

[alph, 2016/08/22 23:51:07]

Added it as a comment.

[panicker, 2016/08/25 23:11:52]

Done.

+      monotonicTimeInSeconds * base::Time::kMicrosecondsPerSecond);
+}
 }  // namespace
 
 RendererSchedulerImpl::RendererSchedulerImpl(
@@ -81,7 +86,7 @@ RendererSchedulerImpl::RendererSchedulerImpl(
       this);
 
   helper_.SetObserver(this);
-  helper_.SetTaskTimeTracker(this);
+  helper_.AddTaskTimeObserver(this);
 }
 
 RendererSchedulerImpl::~RendererSchedulerImpl() {
@@ -101,6 +106,8 @@ RendererSchedulerImpl::~RendererSchedulerImpl() {
   if (virtual_time_domain_)
     UnregisterTimeDomain(virtual_time_domain_.get());
 
+  helper_.RemoveTaskTimeObserver(this);
+
   // Ensure the renderer scheduler was shut down explicitly, because otherwise
   // we could end up having stale pointers to the Blink heap which has been
   // terminated by this point.
@@ -1407,19 +1414,26 @@ void RendererSchedulerImpl::OnTriedToExecuteBlockedTask(
   }
 }
 
-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);
+void RendererSchedulerImpl::reportTaskTime(double start_time,

[Sami, 2016/08/22 15:51:30]

FYI, altimin@ is adding another task time consumer here:
https://codereview.chromium.org/2265873004/

[panicker, 2016/08/22 23:14:15]

Acknowledged.

+                                           double end_time) {
+  base::TimeTicks start_time_ticks = MonotonicTimeInSecondsToTimeTicks(start_time);
+  base::TimeTicks end_time_ticks = MonotonicTimeInSecondsToTimeTicks(end_time);
+
+  MainThreadOnly().queueing_time_estimator.OnToplevelTaskCompleted(start_time_ticks,
+                                                                   end_time_ticks);
   UMA_HISTOGRAM_CUSTOM_COUNTS("RendererScheduler.TaskTime",
-                              (end_time - start_time).InMicroseconds(), 1,
+                              (end_time_ticks - start_time_ticks).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(