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

components/scheduler/child/idle_helper_unittest.cc

Index: components/scheduler/child/idle_helper_unittest.cc
diff --git a/components/scheduler/child/idle_helper_unittest.cc b/components/scheduler/child/idle_helper_unittest.cc
index 5e7f17c727990559cfab9e5f715aaa41d3f076da..fc9d53483966ecc7311e471b7c9e01141a373851 100644
--- a/components/scheduler/child/idle_helper_unittest.cc
+++ b/components/scheduler/child/idle_helper_unittest.cc
@@ -128,11 +128,14 @@ void EndIdlePeriodIdleTask(IdleHelper* idle_helper, base::TimeTicks deadline) {
 
 scoped_refptr<SchedulerTaskRunnerDelegate> CreateTaskRunnerDelegate(
     base::MessageLoop* message_loop,
-    scoped_refptr<cc::OrderedSimpleTaskRunner> mock_task_runner) {
+    scoped_refptr<cc::OrderedSimpleTaskRunner> mock_task_runner,
+    scoped_ptr<TestTimeSource> test_time_source) {
   if (message_loop)
-    return SchedulerTaskRunnerDelegateImpl::Create(message_loop);
+    return SchedulerTaskRunnerDelegateImpl::Create(message_loop,
+                                                   test_time_source.Pass());
 
-  return SchedulerTaskRunnerDelegateForTest::Create(mock_task_runner);
+  return SchedulerTaskRunnerDelegateForTest::Create(mock_task_runner,
+                                                    test_time_source.Pass());
 }
 
 };  // namespace
@@ -172,8 +175,10 @@ class BaseIdleHelperTest : public testing::Test {
                 ? nullptr
                 : new cc::OrderedSimpleTaskRunner(clock_.get(), false)),
         message_loop_(message_loop),
-        main_task_runner_(
-            CreateTaskRunnerDelegate(message_loop, mock_task_runner_)),
+        main_task_runner_(CreateTaskRunnerDelegate(
+            message_loop,
+            mock_task_runner_,
+            make_scoped_ptr(new TestTimeSource(clock_.get())))),
         scheduler_helper_(
             new SchedulerHelper(main_task_runner_,
                                 "test.idle",
@@ -185,10 +190,6 @@ class BaseIdleHelperTest : public testing::Test {
         default_task_runner_(scheduler_helper_->DefaultTaskRunner()),
         idle_task_runner_(idle_helper_->IdleTaskRunner()) {
     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())));
   }
 
   ~BaseIdleHelperTest() override {}