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

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 5faa5e1deb8bc9e4cd328d69779f63b6291e6801..1e7b4e5cd8fa786eacdb6d94ff2d9b5d25a534f4 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
@@ -14,6 +14,7 @@
 #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"
@@ -49,6 +50,9 @@ 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);
@@ -57,6 +61,9 @@ void ReportForegroundRendererTaskLoad(base::TimeTicks time, double load) {
 }
 
 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);