[scheduler] Add TaskDurationPerTaskType.{Foreground,Background} histograms.

Add new histograms to capture per-task-type task duration for different
renderer visibility states separately.

BUG=820494
R=rkaplow@chromium.org
CC=panicker@chromium.org

Change-Id: Icce8e262cc87a4d3f73809abdbcda34a124a1bb9
Reviewed-on: https://chromium-review.googlesource.com/955855Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Alexander Timin <altimin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542222}

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

@@ -96,6 +96,10 @@ RendererMetricsHelper::RendererMetricsHelper(
           DURATION_PER_QUEUE_TYPE_METRIC_NAME ".HiddenMusic"),
       per_frame_status_duration_reporter(DURATION_PER_FRAME_TYPE_METRIC_NAME),
       per_task_type_duration_reporter(DURATION_PER_TASK_TYPE_METRIC_NAME),
+      foreground_per_task_type_duration_reporter(
+          DURATION_PER_TASK_TYPE_METRIC_NAME ".Foreground"),
+      background_per_task_type_duration_reporter(
+          DURATION_PER_TASK_TYPE_METRIC_NAME ".Background"),
       main_thread_task_load_state(MainThreadTaskLoadState::kUnknown) {
   main_thread_load_tracker.Resume(now);
   if (renderer_backgrounded) {
@@ -230,6 +234,9 @@ void RendererMetricsHelper::RecordTaskMetrics(
 
   per_queue_type_task_duration_reporter.RecordTask(queue_type, duration);
 
+  TaskType task_type = static_cast<TaskType>(task.task_type());
+  per_task_type_duration_reporter.RecordTask(task_type, duration);
+
   if (renderer_scheduler_->main_thread_only().renderer_backgrounded) {
     background_per_queue_type_task_duration_reporter.RecordTask(queue_type,
                                                                 duration);
@@ -276,6 +283,8 @@ void RendererMetricsHelper::RecordTaskMetrics(
                 backgrounded_at + base::TimeDelta::FromMinutes(5),
                 std::max(backgrounded_at + base::TimeDelta::FromMinutes(5),
                          end_time)));
+
+    background_per_task_type_duration_reporter.RecordTask(task_type, duration);
   } else {
     foreground_per_queue_type_task_duration_reporter.RecordTask(queue_type,
                                                                 duration);
@@ -310,6 +319,8 @@ void RendererMetricsHelper::RecordTaskMetrics(
                 foregrounded_at + base::TimeDelta::FromMinutes(3),
                 std::max(foregrounded_at + base::TimeDelta::FromMinutes(3),
                          end_time)));
+
+    foreground_per_task_type_duration_reporter.RecordTask(task_type, duration);
   }
 
   if (renderer_scheduler_->main_thread_only().renderer_hidden) {
@@ -354,9 +365,6 @@ void RendererMetricsHelper::RecordTaskMetrics(
     UMA_HISTOGRAM_ENUMERATION(COUNT_PER_FRAME_METRIC_NAME ".LongerThan1s",
                               frame_status, FrameStatus::kCount);
   }
-
-  per_task_type_duration_reporter.RecordTask(
-      static_cast<TaskType>(task.task_type()), duration);
 }
 
 void RendererMetricsHelper::RecordMainThreadTaskLoad(base::TimeTicks time,

third_party/WebKit/Source/platform/scheduler/renderer/renderer_metrics_helper.h

@@ -119,6 +119,10 @@ class PLATFORM_EXPORT RendererMetricsHelper : public MetricsHelper {
   using TaskDurationPerTaskTypeMetricReporter =
       TaskDurationMetricReporter<TaskType>;
   TaskDurationPerTaskTypeMetricReporter per_task_type_duration_reporter;
+  TaskDurationPerTaskTypeMetricReporter
+      foreground_per_task_type_duration_reporter;
+  TaskDurationPerTaskTypeMetricReporter
+      background_per_task_type_duration_reporter;
 
   MainThreadTaskLoadState main_thread_task_load_state;
 

tools/metrics/histograms/histograms.xml

@@ -112719,6 +112719,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <suffix name="Background"/>
   <suffix name="Foreground"/>
   <affected-histogram name="RendererScheduler.TaskCPUDurationPerThreadType"/>
+  <affected-histogram name="RendererScheduler.TaskDurationPerTaskType"/>
   <affected-histogram name="RendererScheduler.TaskDurationPerThreadType"/>
 </histogram_suffixes>