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 60 matching lines @@
   // 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 44 matching lines @@
       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 54 matching lines @@
   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_