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

components/scheduler/child/scheduler_helper_unittest.cc

Index: components/scheduler/child/scheduler_helper_unittest.cc
diff --git a/components/scheduler/child/scheduler_helper_unittest.cc b/components/scheduler/child/scheduler_helper_unittest.cc
index 5d75bb28790913a8021e2dd24b4271ccbba42b1c..9ff623554552cb7a115a117311c6d3900e216419 100644
--- a/components/scheduler/child/scheduler_helper_unittest.cc
+++ b/components/scheduler/child/scheduler_helper_unittest.cc
@@ -46,8 +46,9 @@ class SchedulerHelperTest : public testing::Test {
   SchedulerHelperTest()
       : clock_(new base::SimpleTestTickClock()),
         mock_task_runner_(new cc::OrderedSimpleTaskRunner(clock_.get(), false)),
-        main_task_runner_(
-            SchedulerTaskRunnerDelegateForTest::Create(mock_task_runner_)),
+        main_task_runner_(SchedulerTaskRunnerDelegateForTest::Create(
+            mock_task_runner_,
+            make_scoped_ptr(new TestTimeSource(clock_.get())))),
         scheduler_helper_(new SchedulerHelper(
             main_task_runner_,
             "test.scheduler",
@@ -55,10 +56,6 @@ class SchedulerHelperTest : public testing::Test {
             TRACE_DISABLED_BY_DEFAULT("test.scheduler.dbg"))),
         default_task_runner_(scheduler_helper_->DefaultTaskRunner()) {
     clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
-    scheduler_helper_->SetTimeSourceForTesting(
-        make_scoped_ptr(new TestTimeSource(clock_.get())));
-    scheduler_helper_->GetTaskQueueManagerForTesting()->SetTimeSourceForTesting(
-        make_scoped_ptr(new TestTimeSource(clock_.get())));
   }
 
   ~SchedulerHelperTest() override {}