[Blink-Scheduler] Distinguish between normal and foreground-only renderers for monitoring load.

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

Index: third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.h
diff --git a/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.h b/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.h
index ce486f3ee63766382b47f8f3f4af7d1c57bb4325..a26a2ebd2c14b055836f527799150886888b1c5a 100644
--- a/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.h
+++ b/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.h
@@ -5,6 +5,8 @@
 #ifndef THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_RENDERER_RENDERER_SCHEDULER_IMPL_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_RENDERER_RENDERER_SCHEDULER_IMPL_H_
 
+#include <memory>
+
 #include "base/atomicops.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
@@ -83,7 +85,9 @@ class PLATFORM_EXPORT RendererSchedulerImpl
   static const char* UseCaseToString(UseCase use_case);
   static const char* RAILModeToString(v8::RAILMode rail_mode);
 
-  RendererSchedulerImpl(scoped_refptr<SchedulerTqmDelegate> main_task_runner);
+  RendererSchedulerImpl(
+      scoped_refptr<SchedulerTqmDelegate> main_task_runner,
+      RendererType type = RendererType::kForegroundAndBackground);
   ~RendererSchedulerImpl() override;
 
   // RendererScheduler implementation:
@@ -455,14 +459,16 @@ class PLATFORM_EXPORT RendererSchedulerImpl
     MainThreadOnly(RendererSchedulerImpl* renderer_scheduler_impl,
                    const scoped_refptr<TaskQueue>& compositor_task_runner,
                    base::TickClock* time_source,
-                   base::TimeTicks now);
+                   base::TimeTicks now,
+                   RendererType type);
     ~MainThreadOnly();
 
     TaskCostEstimator loading_task_cost_estimator;
     TaskCostEstimator timer_task_cost_estimator;
     IdleTimeEstimator idle_time_estimator;
-    ThreadLoadTracker background_main_thread_load_tracker;
-    ThreadLoadTracker foreground_main_thread_load_tracker;
+    std::unique_ptr<ThreadLoadTracker> background_main_thread_load_tracker;
+    std::unique_ptr<ThreadLoadTracker> foreground_main_thread_load_tracker;
+    std::unique_ptr<ThreadLoadTracker> foreground_only_main_thread_load_tracker;
     UseCase current_use_case;
     Policy current_policy;
     base::TimeTicks current_policy_expiration_time;
@@ -537,6 +543,8 @@ class PLATFORM_EXPORT RendererSchedulerImpl
     }
   };
 
+  RendererType type_;
+
   // Don't access main_thread_only_, instead use MainThreadOnly().
   MainThreadOnly main_thread_only_;
   MainThreadOnly& GetMainThreadOnly() {