Scheduler/child/TimeSource could be replaced with base/time/DefaultTickClock.

components/scheduler/child/scheduler_helper.h

Index: components/scheduler/child/scheduler_helper.h
diff --git a/components/scheduler/child/scheduler_helper.h b/components/scheduler/child/scheduler_helper.h
index a28e02233b974c6728da47b16d40a704b4e1ae0b..7abd6681331f9acb6d7eb83f9e2e7f42540697ee 100644
--- a/components/scheduler/child/scheduler_helper.h
+++ b/components/scheduler/child/scheduler_helper.h
@@ -5,9 +5,9 @@
 #ifndef COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
 #define COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
 
+#include "base/time/default_tick_clock.h"

[Sami, 2015/06/04 13:51:47]

Could you forward declare this instead?

[Jimmy Jo, 2015/06/05 00:45:09]

Done.

 #include "components/scheduler/child/prioritizing_task_queue_selector.h"
 #include "components/scheduler/child/task_queue_manager.h"
-#include "components/scheduler/child/time_source.h"
 #include "components/scheduler/scheduler_export.h"
 
 namespace scheduler {
@@ -93,7 +93,7 @@ class SCHEDULER_EXPORT SchedulerHelper {
   uint64 GetAndClearTaskWasRunOnQueueBitmap();
 
   // Test helpers.
-  void SetTimeSourceForTesting(scoped_ptr<TimeSource> time_source);
+  void SetTimeSourceForTesting(scoped_ptr<base::DefaultTickClock> time_source);

[Sami, 2015/06/04 13:51:47]

I think this should be base::TickClock since we don't really care that
DefaultTickClock is involved.

[Jimmy Jo, 2015/06/05 00:45:09]

Done.

   void SetWorkBatchSizeForTesting(size_t work_batch_size);
   TaskQueueManager* GetTaskQueueManagerForTesting();
 
@@ -110,7 +110,7 @@ class SCHEDULER_EXPORT SchedulerHelper {
   scoped_refptr<base::SingleThreadTaskRunner> control_after_wakeup_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> default_task_runner_;
 
-  scoped_ptr<TimeSource> time_source_;
+  scoped_ptr<base::DefaultTickClock> time_source_;

[Sami, 2015/06/04 13:51:47]

base::TickClock here too.

[Jimmy Jo, 2015/06/05 00:45:09]

Done.

 
   const char* tracing_category_;
   const char* disabled_by_default_tracing_category_;