Force events to be non blocking if main thread is unresponsive.

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 77705b4627e7dc60e28fb7bebe752781e99bd79e..38214dcd7ad3ef90dd3b3bf8884542f7a49c75c2 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
@@ -119,6 +119,7 @@ class BLINK_PLATFORM_EXPORT RendererSchedulerImpl
   void SetTopLevelBlameContext(
       base::trace_event::BlameContext* blame_context) override;
   void SetRAILModeObserver(RAILModeObserver* observer) override;
+  bool ShouldForceEventsNonBlockingForUnresponsiveMainThread() const override;
 
   // RenderWidgetSignals::Observer implementation:
   void SetAllRenderWidgetsHidden(bool hidden) override;
@@ -131,6 +132,7 @@ class BLINK_PLATFORM_EXPORT RendererSchedulerImpl
                                    const base::PendingTask& task) override;
 
   // TaskTimeTracker implementation:
+  void ReportTaskStartTime(base::TimeTicks start_time) override;
   void ReportTaskTime(base::TimeTicks start_time,
                       base::TimeTicks end_time) override;
 
@@ -372,14 +374,12 @@ class BLINK_PLATFORM_EXPORT RendererSchedulerImpl
   // (the accessors) for the following data members.
 
   struct MainThreadOnly {
-    MainThreadOnly(RendererSchedulerImpl* renderer_scheduler_impl,
-                   const scoped_refptr<TaskQueue>& compositor_task_runner,
+    MainThreadOnly(const scoped_refptr<TaskQueue>& compositor_task_runner,
                    base::TickClock* time_source);
     ~MainThreadOnly();
 
     TaskCostEstimator loading_task_cost_estimator;
     TaskCostEstimator timer_task_cost_estimator;
-    QueueingTimeEstimator queueing_time_estimator;
     LongTaskTracker long_task_tracker;
     IdleTimeEstimator idle_time_estimator;
     UseCase current_use_case;
@@ -412,13 +412,14 @@ class BLINK_PLATFORM_EXPORT RendererSchedulerImpl
   };
 
   struct AnyThread {
-    AnyThread();
+    AnyThread(RendererSchedulerImpl* renderer_scheduler_impl);
     ~AnyThread();
 
     base::TimeTicks last_idle_period_end_time;
     base::TimeTicks rails_loading_priority_deadline;
     base::TimeTicks fling_compositor_escalation_deadline;
     UserModel user_model;
+    QueueingTimeEstimator queueing_time_estimator;
     bool awaiting_touch_start_response;
     bool in_idle_period;
     bool begin_main_frame_on_critical_path;