Report the duration of sampled tasks with histogram.

components/scheduler/renderer/renderer_scheduler_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/scheduler/renderer/renderer_scheduler_impl.h"
 
 #include "base/bind.h"
 #include "base/debug/stack_trace.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 1376 matching lines @@
         " and https://crbug.com/574343#c40 for more information.");
   }
 }
 
 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::OnQueueingTimeForWindowEstimated(
     base::TimeDelta queueing_time) {
   UMA_HISTOGRAM_TIMES("RendererScheduler.ExpectedTaskQueueingDuration",
                       queueing_time);
@@ skipping 36 matching lines @@
       return "idle";
     case v8::PERFORMANCE_LOAD:
       return "load";
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
 }  // namespace scheduler