scheduler: Remove task observer shenanigans

components/scheduler/child/scheduler_task_runner_delegate_for_test.h

 // 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.
 
 #ifndef CONTENT_RENDERER_SCHEDULER_TASK_RUNNER_DELEGATE_FOR_TEST_H_
 #define CONTENT_RENDERER_SCHEDULER_TASK_RUNNER_DELEGATE_FOR_TEST_H_
 
 #include "components/scheduler/child/scheduler_task_runner_delegate.h"
 
 namespace scheduler {
@@ skipping 10 matching lines @@
       scoped_refptr<base::SingleThreadTaskRunner> task_runner) override;
   void RestoreDefaultTaskRunner() override;
   bool PostDelayedTask(const tracked_objects::Location& from_here,
                        const base::Closure& task,
                        base::TimeDelta delay) override;
   bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
                                   const base::Closure& task,
                                   base::TimeDelta delay) override;
   bool RunsTasksOnCurrentThread() const override;
   bool IsNested() const override;
-  void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer) override;
-  void RemoveTaskObserver(
-      base::MessageLoop::TaskObserver* task_observer) override;
 
   base::SingleThreadTaskRunner* default_task_runner() const {
     return default_task_runner_.get();
   }
 
  protected:
   ~SchedulerTaskRunnerDelegateForTest() override;
 
  private:
   explicit SchedulerTaskRunnerDelegateForTest(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner);
 
   scoped_refptr<base::SingleThreadTaskRunner> default_task_runner_;
 
   scoped_refptr<NestableTaskRunnerForTest> task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerTaskRunnerDelegateForTest);
 };
 
 }  // namespace scheduler
 
 #endif  // CONTENT_RENDERER_SCHEDULER_SCHEDULER_TASK_RUNNER_DELEGATE_FOR_TEST_H_