message: Document expected thread safety of the TaskQueue interface
  Cr-Commit-Position: refs/heads/master@{#33032}
diff: @@ -27,12 +27,14 @@ class RTC_LOCKABLE RTC_EXPORT TaskQueueBase {
  // Starts destruction of the task queue.
  // On return ensures no task are running and no new tasks are able to start
  // on the task queue.
  - // Responsible for deallocation. Deallocation may happen syncrhoniously during
  + // Responsible for deallocation. Deallocation may happen synchronously during
  // Delete or asynchronously after Delete returns.
  // Code not running on the TaskQueue should not make any assumption when
  // TaskQueue is deallocated and thus should not call any methods after Delete.
  // Code running on the TaskQueue should not call Delete, but can assume
  // TaskQueue still exists and may call other methods, e.g. PostTask.
  + // Should be called on the same task queue or thread that this task queue
  + // was created on.
  virtual void Delete() = 0;
  // Schedules a task to execute. Tasks are executed in FIFO order.
  @@ -43,17 +45,20 @@ class RTC_LOCKABLE RTC_EXPORT TaskQueueBase {
  // TaskQueue or it may happen asynchronously after TaskQueue is deleted.
  // This may vary from one implementation to the next so assumptions about
  // lifetimes of pending tasks should not be made.
  + // May be called on any thread or task queue, including this task queue.
  virtual void PostTask(std::unique_ptr<QueuedTask> task) = 0;
  // Schedules a task to execute a specified number of milliseconds from when
  // the call is made. The precision should be considered as "best effort"
  // and in some cases, such as on Windows when all high precision timers have
  // been used up, can be off by as much as 15 millseconds.
  + // May be called on any thread or task queue, including this task queue.
  virtual void PostDelayedTask(std::unique_ptr<QueuedTask> task,
  uint32_t milliseconds) = 0;
  // Returns the task queue that is running the current thread.
  // Returns nullptr if this thread is not associated with any task queue.
  + // May be called on any thread or task queue, including this task queue.
  static TaskQueueBase* Current();
  bool IsCurrent() const { return Current() == this; }
  