Adds a flag to support "Virtual Time" to the blink scheduler

components/scheduler/child/worker_scheduler_impl_unittest.cc

Index: components/scheduler/child/worker_scheduler_impl_unittest.cc
diff --git a/components/scheduler/child/worker_scheduler_impl_unittest.cc b/components/scheduler/child/worker_scheduler_impl_unittest.cc
index 47e0c68c8018a08002d49d5d5c7c89d36622ac54..8a82c175869bff441453c9d5176630b5b16fba7d 100644
--- a/components/scheduler/child/worker_scheduler_impl_unittest.cc
+++ b/components/scheduler/child/worker_scheduler_impl_unittest.cc
@@ -92,18 +92,13 @@ class WorkerSchedulerImplTest : public testing::Test {
   WorkerSchedulerImplTest()
       : clock_(new base::SimpleTestTickClock()),
         mock_task_runner_(new cc::OrderedSimpleTaskRunner(clock_.get(), true)),
-        main_task_runner_(
-            SchedulerTaskRunnerDelegateForTest::Create(mock_task_runner_)),
+        main_task_runner_(SchedulerTaskRunnerDelegateForTest::Create(
+            mock_task_runner_,
+            make_scoped_ptr(new TestTimeSource(clock_.get())))),
         scheduler_(
             new WorkerSchedulerImplForTest(main_task_runner_, clock_.get())),
         timeline_(nullptr) {
     clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
-    scheduler_->GetSchedulerHelperForTesting()->SetTimeSourceForTesting(
-        make_scoped_ptr(new TestTimeSource(clock_.get())));
-    scheduler_->GetSchedulerHelperForTesting()
-        ->GetTaskQueueManagerForTesting()
-        ->SetTimeSourceForTesting(
-            make_scoped_ptr(new TestTimeSource(clock_.get())));
   }
 
   ~WorkerSchedulerImplTest() override {}