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

third_party/WebKit/Source/platform/scheduler/base/task_queue_manager_unittest.cc

Index: third_party/WebKit/Source/platform/scheduler/base/task_queue_manager_unittest.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/base/task_queue_manager_unittest.cc b/third_party/WebKit/Source/platform/scheduler/base/task_queue_manager_unittest.cc
index 83a2476b3a7e19a4ebb3569b508c7c78177d9092..edd7ad475f170df66da22aafa4beb088ec11ff18 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/task_queue_manager_unittest.cc
+++ b/third_party/WebKit/Source/platform/scheduler/base/task_queue_manager_unittest.cc
@@ -2075,5 +2075,35 @@ TEST_F(TaskQueueManagerTest, TimeDomainWakeUpOnlyCancelledIfAllUsesCancelled) {
   EXPECT_THAT(run_times, ElementsAre(start_time + delay3, start_time + delay4));
 }
 
+TEST_F(TaskQueueManagerTest, DeferredTaskTimeObservation) {
+  InitializeWithRealMessageLoop(1u);
+  now_src_->SetNowTicks(base::TimeTicks() +
+                        base::TimeDelta::FromMicroseconds(10000));
+
+  TestTaskTimeObserver test_task_time_observer;
+  manager_->AddTaskTimeObserver(&test_task_time_observer);
+
+  std::vector<EnqueueOrder> run_order;
+  runners_[0]->PostTask(FROM_HERE, base::Bind(&TestTask, 1, &run_order));
+
+  std::vector<std::pair<base::Closure, bool>> tasks_to_post_from_nested_loop;
+  tasks_to_post_from_nested_loop.push_back(
+      std::make_pair(base::Bind(&TestTask, 1, &run_order), false));
+
+  runners_[0]->PostTask(
+      FROM_HERE, base::Bind(&PostFromNestedRunloop, message_loop_.get(),
+                            base::RetainedRef(runners_[0]),
+                            base::Unretained(&tasks_to_post_from_nested_loop)));
+
+  base::RunLoop().RunUntilIdle();
+
+  // The task is deferred once, and then actually executed, leading to a pair of
+  // entries.
+  EXPECT_THAT(test_task_time_observer.task_start_times(),
+              ElementsAre(0.01, 0.01));
+  EXPECT_THAT(test_task_time_observer.task_end_times(),
+              ElementsAre(0.01, 0.01));
+}
+
 }  // namespace scheduler
 }  // namespace blink