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

third_party/WebKit/Source/platform/scheduler/base/queueing_time_estimator.h

Index: third_party/WebKit/Source/platform/scheduler/base/queueing_time_estimator.h
diff --git a/third_party/WebKit/Source/platform/scheduler/base/queueing_time_estimator.h b/third_party/WebKit/Source/platform/scheduler/base/queueing_time_estimator.h
index 21db2557f17485ea8c0dc6347c5ab92914f6d7b4..18ac433107dcf8cb42854b19105e042ace8377a2 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/queueing_time_estimator.h
+++ b/third_party/WebKit/Source/platform/scheduler/base/queueing_time_estimator.h
@@ -9,6 +9,8 @@
 #include "base/time/time.h"
 #include "public/platform/WebCommon.h"
 
+#include <memory>
+
 namespace base {
 class TickClock;
 }
@@ -33,10 +35,15 @@ class BLINK_PLATFORM_EXPORT QueueingTimeEstimator {
 
   QueueingTimeEstimator(Client* client, base::TimeDelta window_duration);
 
-  void OnToplevelTaskCompleted(base::TimeTicks task_start_time,
+  void OnTopLevelTaskStarted(base::TimeTicks task_start_time);
+  void OnTopLevelTaskCompleted(base::TimeTicks task_start_time,
                                base::TimeTicks task_end_time);
 
+  base::TimeDelta EstimateQueueingTimeIncludingCurrentTask(base::TimeTicks now) const;
+
  private:
+  // Returns a clone of this object, with the |client_| set to |client|.
+  std::unique_ptr<QueueingTimeEstimator> CloneWithClient(Client* client) const;
   bool TimePastWindowEnd(base::TimeTicks task_end_time);
   Client* client_;  // NOT OWNED.
 
@@ -44,6 +51,9 @@ class BLINK_PLATFORM_EXPORT QueueingTimeEstimator {
   base::TimeDelta window_duration_;
   base::TimeTicks window_start_time_;
 
+  // Only used when including active task in estimated queueing time.
+  base::TimeTicks current_task_start_time_;
+
   DISALLOW_COPY_AND_ASSIGN(QueueingTimeEstimator);
 };