[scheduler] Don't report thread load to UMA when throttling is disabled.

third_party/WebKit/Source/platform/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 "platform/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"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "cc/output/begin_frame_args.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "platform/scheduler/base/real_time_domain.h"
 #include "platform/scheduler/base/task_queue_impl.h"
 #include "platform/scheduler/base/task_queue_selector.h"
 #include "platform/scheduler/base/virtual_time_domain.h"
 #include "platform/scheduler/child/scheduler_tqm_delegate.h"
 #include "platform/scheduler/renderer/auto_advancing_virtual_time_domain.h"
 #include "platform/scheduler/renderer/task_queue_throttler.h"
 #include "platform/scheduler/renderer/web_view_scheduler_impl.h"
 #include "platform/scheduler/renderer/webthread_impl_for_renderer_scheduler.h"
 
@@ skipping 15 matching lines @@
 const double kFastCompositingIdleTimeThreshold = .2;
 constexpr base::TimeDelta kThreadLoadTrackerReportingInterval =
     base::TimeDelta::FromMinutes(1);
 constexpr base::TimeDelta kThreadLoadTrackerWaitingPeriodBeforeReporting =
     base::TimeDelta::FromMinutes(2);
 // We do not throttle anything while audio is played and shortly after that.
 constexpr base::TimeDelta kThrottlingDelayAfterAudioIsPlayed =
     base::TimeDelta::FromSeconds(5);
 
 void ReportForegroundRendererTaskLoad(base::TimeTicks time, double load) {
+  if (!blink::RuntimeEnabledFeatures::timerThrottlingForBackgroundTabsEnabled())
+    return;
+
   int load_percentage = static_cast<int>(load * 100);
   UMA_HISTOGRAM_PERCENTAGE("RendererScheduler.ForegroundRendererMainThreadLoad",
                            load_percentage);
   TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"),
                  "RendererScheduler.ForegroundRendererLoad", load_percentage);
 }
 
 void ReportBackgroundRendererTaskLoad(base::TimeTicks time, double load) {
+  if (!blink::RuntimeEnabledFeatures::timerThrottlingForBackgroundTabsEnabled())
+    return;
+
   int load_percentage = static_cast<int>(load * 100);
   UMA_HISTOGRAM_PERCENTAGE("RendererScheduler.BackgroundRendererMainThreadLoad",
                            load_percentage);
   TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"),
                  "RendererScheduler.BackgroundRendererLoad", load_percentage);
 }
 
 base::TimeTicks MonotonicTimeInSecondsToTimeTicks(
     double monotonicTimeInSeconds) {
   return base::TimeTicks() +
@@ skipping 1813 matching lines @@
     case TimeDomainType::VIRTUAL:
       return "virtual";
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
 }  // namespace scheduler
 }  // namespace blink