Adds a flag to support "Virtual Time" to the blink scheduler

components/scheduler/base/task_queue_manager.h

 // Copyright 2014 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_BASE_TASK_QUEUE_MANAGER_H_
 #define CONTENT_RENDERER_SCHEDULER_BASE_TASK_QUEUE_MANAGER_H_
 
 #include <map>
 
 #include "base/atomic_sequence_num.h"
@@ skipping 16 matching lines @@
 class TracedValue;
 }  // namespace trace_event
 }  // namespace base
 
 namespace scheduler {
 namespace internal {
 class LazyNow;
 class TaskQueueImpl;
 }  // namespace internal
 
-class NestableSingleThreadTaskRunner;
+class TaskQueueManagerDelegate;
 
 // The task queue manager provides N task queues and a selector interface for
 // choosing which task queue to service next. Each task queue consists of two
 // sub queues:
 //
 // 1. Incoming task queue. Tasks that are posted get immediately appended here.
 //    When a task is appended into an empty incoming queue, the task manager
 //    work function (DoWork) is scheduled to run on the main task runner.
 //
 // 2. Work queue. If a work queue is empty when DoWork() is entered, tasks from
 //    the incoming task queue (if any) are moved here. The work queues are
 //    registered with the selector as input to the scheduling decision.
 //
 class SCHEDULER_EXPORT TaskQueueManager
     : public internal::TaskQueueSelector::Observer {
  public:
-  // Create a task queue manager where |main_task_runner| identifies the thread
+  // Create a task queue manager where |delegate| identifies the thread
   // on which where the tasks are  eventually run. Category strings must have
   // application lifetime (statics or literals). They may not include " chars.
-  TaskQueueManager(
-      scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner,
-      const char* tracing_category,
-      const char* disabled_by_default_tracing_category,
-      const char* disabled_by_default_verbose_tracing_category);
+  TaskQueueManager(scoped_refptr<TaskQueueManagerDelegate> delegate,
+                   const char* tracing_category,
+                   const char* disabled_by_default_tracing_category,
+                   const char* disabled_by_default_verbose_tracing_category);
   ~TaskQueueManager() override;
 
   // Returns the time of the next pending delayed task in any queue.  Ignores
   // any delayed tasks whose delay has expired. Returns a null TimeTicks object
   // if no tasks are pending.  NOTE this is somewhat expensive since every queue
   // will get locked.
   base::TimeTicks NextPendingDelayedTaskRunTime();
 
   // Set the number of tasks executed in a single invocation of the task queue
   // manager. Increasing the batch size can reduce the overhead of yielding
   // back to the main message loop -- at the cost of potentially delaying other
   // tasks posted to the main loop. The batch size is 1 by default.
   void SetWorkBatchSize(int work_batch_size);
 
   // These functions can only be called on the same thread that the task queue
   // manager executes its tasks on.
   void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer);
   void RemoveTaskObserver(base::MessageLoop::TaskObserver* task_observer);
 
-  void SetTimeSourceForTesting(scoped_ptr<base::TickClock> time_source);
-
   // Returns true if any task from a monitored task queue was was run since the
   // last call to GetAndClearSystemIsQuiescentBit.
   bool GetAndClearSystemIsQuiescentBit();
 
   // Creates a task queue with the given |spec|.  Must be called on the thread
   // this class was created on.
   scoped_refptr<internal::TaskQueueImpl> NewTaskQueue(
       const TaskQueue::Spec& spec);
 
   class SCHEDULER_EXPORT Observer {
    public:
     virtual ~Observer() {}
 
     // Called when |queue| is unregistered.
     virtual void OnUnregisterTaskQueue(
         const scoped_refptr<internal::TaskQueueImpl>& queue) = 0;
   };
 
   // Called once to set the Observer. This function is called on the main
   // thread. If |observer| is null, then no callbacks will occur.
   // Note |observer| is expected to outlive the SchedulerHelper.
   void SetObserver(Observer* observer);
 
+  // Returns the TickClock used by the TaskQueueManager.
+  base::TickClock* tick_clock() const;
+
  private:
   friend class internal::LazyNow;
   friend class internal::TaskQueueImpl;
   friend class TaskQueueManagerTest;
 
   class DeletionSentinel : public base::RefCounted<DeletionSentinel> {
    private:
     friend class base::RefCounted<DeletionSentinel>;
     ~DeletionSentinel() {}
   };
@@ skipping 37 matching lines @@
   enum class ProcessTaskResult {
     DEFERRED,
     EXECUTED,
     TASK_QUEUE_MANAGER_DELETED
   };
   ProcessTaskResult ProcessTaskFromWorkQueue(
       internal::TaskQueueImpl* queue,
       internal::TaskQueueImpl::Task* out_previous_task);
 
   bool RunsTasksOnCurrentThread() const;
-  bool PostDelayedTask(const tracked_objects::Location& from_here,
-                       const base::Closure& task,
-                       base::TimeDelta delay);
   bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
                                   const base::Closure& task,
                                   base::TimeDelta delay);
 
-  base::TimeTicks Now() const;
-
   int GetNextSequenceNumber();
 
   scoped_refptr<base::trace_event::ConvertableToTraceFormat>
   AsValueWithSelectorResult(bool should_run,
                             internal::TaskQueueImpl* selected_queue) const;
 
   // Causes DoWork to start calling UpdateWorkQueue for |queue|. Can be called
   // from any thread.
   void RegisterAsUpdatableTaskQueue(internal::TaskQueueImpl* queue);
 
@@ skipping 39 matching lines @@
 
   typedef std::multimap<base::TimeTicks, internal::TaskQueueImpl*>
       DelayedWakeupMultimap;
 
   DelayedWakeupMultimap delayed_wakeup_multimap_;
 
   base::AtomicSequenceNumber task_sequence_num_;
   base::debug::TaskAnnotator task_annotator_;
 
   base::ThreadChecker main_thread_checker_;
-  scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner_;
+  scoped_refptr<TaskQueueManagerDelegate> delegate_;
   internal::TaskQueueSelector selector_;
 
   base::Closure do_work_from_main_thread_closure_;
   base::Closure do_work_from_other_thread_closure_;
   base::Closure delayed_queue_wakeup_closure_;
 
   bool task_was_run_on_quiescence_monitored_queue_;
 
   // The pending_dowork_count_ is only tracked on the main thread since that's
   // where re-entrant problems happen.
   int pending_dowork_count_;
 
   int work_batch_size_;
 
-  scoped_ptr<base::TickClock> time_source_;
-
   base::ObserverList<base::MessageLoop::TaskObserver> task_observers_;
 
   const char* tracing_category_;
   const char* disabled_by_default_tracing_category_;
   const char* disabled_by_default_verbose_tracing_category_;
 
   Observer* observer_;  // NOT OWNED
   scoped_refptr<DeletionSentinel> deletion_sentinel_;
   base::WeakPtrFactory<TaskQueueManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueueManager);
 };
 
 }  // namespace scheduler
 
 #endif  // CONTENT_RENDERER_SCHEDULER_BASE_TASK_QUEUE_MANAGER_H_