scheduler: Remove task observer shenanigans

components/scheduler/child/scheduler_task_runner_delegate_for_test.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/scheduler/child/scheduler_task_runner_delegate_for_test.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "components/scheduler/child/nestable_task_runner_for_test.h"
 
@@ skipping 37 matching lines @@
 }
 
 bool SchedulerTaskRunnerDelegateForTest::RunsTasksOnCurrentThread() const {
   return task_runner_->RunsTasksOnCurrentThread();
 }
 
 bool SchedulerTaskRunnerDelegateForTest::IsNested() const {
   return task_runner_->IsNested();
 }
 
-void SchedulerTaskRunnerDelegateForTest::AddTaskObserver(
-    base::MessageLoop::TaskObserver* task_observer) {
-  task_runner_->AddTaskObserver(task_observer);
-}
-
-void SchedulerTaskRunnerDelegateForTest::RemoveTaskObserver(
-    base::MessageLoop::TaskObserver* task_observer) {
-  task_runner_->RemoveTaskObserver(task_observer);
-}
-
 }  // namespace scheduler