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

components/scheduler/base/task_queue_manager.h

Index: components/scheduler/base/task_queue_manager.h
diff --git a/components/scheduler/base/task_queue_manager.h b/components/scheduler/base/task_queue_manager.h
index 834024b51e2eeedc5c5b0dc3f8bd987d45042929..03fff4763fe1e7bd7dd5c2d5681ab778fc2aa343 100644
--- a/components/scheduler/base/task_queue_manager.h
+++ b/components/scheduler/base/task_queue_manager.h
@@ -78,8 +78,6 @@ class SCHEDULER_EXPORT TaskQueueManager
   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();
@@ -103,6 +101,9 @@ class SCHEDULER_EXPORT TaskQueueManager
   // 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;
@@ -167,8 +168,6 @@ class SCHEDULER_EXPORT TaskQueueManager
                                   const base::Closure& task,
                                   base::TimeDelta delay);
 
-  base::TimeTicks Now() const;
-
   int GetNextSequenceNumber();
 
   scoped_refptr<base::trace_event::ConvertableToTraceFormat>
@@ -243,8 +242,6 @@ class SCHEDULER_EXPORT TaskQueueManager
 
   int work_batch_size_;
 
-  scoped_ptr<base::TickClock> time_source_;
-
   base::ObserverList<base::MessageLoop::TaskObserver> task_observers_;
 
   const char* tracing_category_;