components/scheduler/child/nestable_single_thread_task_runner.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_SCHEDULER_CHILD_NESTABLE_SINGLE_THREAD_TASK_RUNNER_H_
   6 #define COMPONENTS_SCHEDULER_CHILD_NESTABLE_SINGLE_THREAD_TASK_RUNNER_H_
   7
   8 #include "base/single_thread_task_runner.h"
   9 #include "base/message_loop/message_loop.h"
  10 #include "components/scheduler/scheduler_export.h"
  11
  12 namespace scheduler {
  13
  14 // A single thread task runner which exposes whether it is running nested.
  15 class SCHEDULER_EXPORT NestableSingleThreadTaskRunner
  16     : public base::SingleThreadTaskRunner {
  17  public:
  18   NestableSingleThreadTaskRunner() {}
  19
  20   // Returns true if the task runner is nested (i.e., running a run loop within
  21   // a nested task).
  22   virtual bool IsNested() const = 0;
  23
  24   // Adds and removes MessageLoop::TaskObservers to the task runner.
  25   virtual void AddTaskObserver(
  26       base::MessageLoop::TaskObserver* task_observer) = 0;
  27   virtual void RemoveTaskObserver(
  28       base::MessageLoop::TaskObserver* task_observer) = 0;
  29
  30  protected:
  31   ~NestableSingleThreadTaskRunner() override {}
  32
  33   DISALLOW_COPY_AND_ASSIGN(NestableSingleThreadTaskRunner);
  34 };
  35
  36 }  // namespace scheduler
  37
  38 #endif  // COMPONENTS_SCHEDULER_CHILD_NESTABLE_SINGLE_THREAD_TASK_RUNNER_H_