Revert of Redirect the MessageLoop's task runner to the renderer 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 5dcf6ec79569500b90a58a5a4e49e872c2ef8935..85c811aa86ece8aa1760e5893aa544c18bffec0c 100644
--- a/components/scheduler/child/scheduler_helper_unittest.cc
+++ b/components/scheduler/child/scheduler_helper_unittest.cc
@@ -7,7 +7,8 @@
 #include "base/callback.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "cc/test/ordered_simple_task_runner.h"
-#include "components/scheduler/child/scheduler_task_runner_delegate_for_test.h"
+#include "components/scheduler/child/nestable_task_runner_for_test.h"
+#include "components/scheduler/child/scheduler_message_loop_delegate.h"
 #include "components/scheduler/child/test_time_source.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -45,10 +46,10 @@
   SchedulerHelperTest()
       : clock_(new base::SimpleTestTickClock()),
         mock_task_runner_(new cc::OrderedSimpleTaskRunner(clock_.get(), false)),
-        main_task_runner_(
-            SchedulerTaskRunnerDelegateForTest::Create(mock_task_runner_)),
+        nestable_task_runner_(
+            NestableTaskRunnerForTest::Create(mock_task_runner_)),
         scheduler_helper_(
-            new SchedulerHelper(main_task_runner_,
+            new SchedulerHelper(nestable_task_runner_,
                                 "test.scheduler",
                                 TRACE_DISABLED_BY_DEFAULT("test.scheduler"),
                                 TRACE_DISABLED_BY_DEFAULT("test.scheduler.dbg"),
@@ -92,7 +93,7 @@
   scoped_ptr<base::SimpleTestTickClock> clock_;
   scoped_refptr<cc::OrderedSimpleTaskRunner> mock_task_runner_;
 
-  scoped_refptr<SchedulerTaskRunnerDelegateForTest> main_task_runner_;
+  scoped_refptr<NestableSingleThreadTaskRunner> nestable_task_runner_;
   scoped_ptr<SchedulerHelper> scheduler_helper_;
   scoped_refptr<base::SingleThreadTaskRunner> default_task_runner_;
 
@@ -138,11 +139,4 @@
   CheckAllTaskQueueIdToString();
 }
 
-TEST_F(SchedulerHelperTest, DefaultTaskRunnerRegistration) {
-  EXPECT_EQ(main_task_runner_->default_task_runner(),
-            scheduler_helper_->DefaultTaskRunner());
-  scheduler_helper_->Shutdown();
-  EXPECT_EQ(nullptr, main_task_runner_->default_task_runner());
-}
-
 }  // namespace scheduler