Fixing and enhancing OrderedSimpleTaskRunner to allow 100% deterministic tests.

cc/scheduler/scheduler.h

 // Copyright 2011 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 CC_SCHEDULER_SCHEDULER_H_
 #define CC_SCHEDULER_SCHEDULER_H_
 
 #include <deque>
 #include <string>
 
@@ skipping 136 matching lines @@
 
   bool IsBeginMainFrameSent() const;
   void SetContinuousPainting(bool continuous_painting) {
     state_machine_.SetContinuousPainting(continuous_painting);
   }
 
  protected:
   class CC_EXPORT SyntheticBeginFrameSource : public TimeSourceClient {
    public:
     SyntheticBeginFrameSource(Scheduler* scheduler,
-                              base::SingleThreadTaskRunner* task_runner);
+                              scoped_refptr<DelayBasedTimeSource> time_source);

[Sami, 2014/08/29 13:13:51]

Could this be a scoped_ptr instead? Looks like this class could take ownership
of the time source.

[mithro-old, 2014/09/01 06:19:46]

DelayBasedTimeSource is ref counted, so have to use a scoped_refptr here. I
don't want to change DelayBasedTimeSource in this CL, but definite candidate for
fixes in the future.

     virtual ~SyntheticBeginFrameSource();
 
     // Updates the phase and frequency of the timer.
     void CommitVSyncParameters(base::TimeTicks timebase,
                                base::TimeDelta interval);
 
     // Activates future BeginFrames and, if activating, pushes the most
     // recently missed BeginFrame to the back of a retroactive queue.
     void SetNeedsBeginFrame(bool needs_begin_frame,
                             std::deque<BeginFrameArgs>* begin_retro_frame_args);
@@ skipping 10 matching lines @@
 
     Scheduler* scheduler_;
     scoped_refptr<DelayBasedTimeSource> time_source_;
   };
 
   Scheduler(SchedulerClient* client,
             const SchedulerSettings& scheduler_settings,
             int layer_tree_host_id,
             const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
 
+  virtual base::TimeTicks Now() const;
+
   const SchedulerSettings settings_;
   SchedulerClient* client_;
   int layer_tree_host_id_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   base::TimeDelta vsync_interval_;
   base::TimeDelta estimated_parent_draw_time_;
 
   bool last_set_needs_begin_frame_;
   bool begin_unthrottled_frame_posted_;
@@ skipping 35 matching lines @@
   void SetupSyntheticBeginFrames();
 
   base::WeakPtrFactory<Scheduler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Scheduler);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_H_