|  | // Copyright 2018 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 BASE_TASK_SEQUENCE_MANAGER_TASK_TIME_OBSERVER_H_ | 
|  | #define BASE_TASK_SEQUENCE_MANAGER_TASK_TIME_OBSERVER_H_ | 
|  |  | 
|  | #include "base/time/time.h" | 
|  |  | 
|  | namespace base { | 
|  | namespace sequence_manager { | 
|  |  | 
|  | // TaskTimeObserver provides an API for observing completion of tasks. | 
|  | class TaskTimeObserver { | 
|  | public: | 
|  | TaskTimeObserver() = default; | 
|  | virtual ~TaskTimeObserver() = default; | 
|  |  | 
|  | // To be called when task is about to start. | 
|  | virtual void WillProcessTask(TimeTicks start_time) = 0; | 
|  |  | 
|  | // To be called when task is completed. | 
|  | virtual void DidProcessTask(TimeTicks start_time, TimeTicks end_time) = 0; | 
|  |  | 
|  | private: | 
|  | DISALLOW_COPY_AND_ASSIGN(TaskTimeObserver); | 
|  | }; | 
|  |  | 
|  | }  // namespace sequence_manager | 
|  | }  // namespace base | 
|  |  | 
|  | #endif  // BASE_TASK_SEQUENCE_MANAGER_TASK_TIME_OBSERVER_H_ |