cc: Control defer_commits logic by Scheduler

cc/scheduler/scheduler_state_machine.h

Index: cc/scheduler/scheduler_state_machine.h
diff --git a/cc/scheduler/scheduler_state_machine.h b/cc/scheduler/scheduler_state_machine.h
index a63a683e90787692fdad05fc2ca6c229b2f342e4..28a07f2620cac44af05b2fd584a31b64532472b7 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -244,6 +244,8 @@ class CC_EXPORT SchedulerStateMachine {
         impl_latency_takes_priority_on_battery;
   }
 
+  void SetDeferCommits(bool defer_commits);
+
   // TODO(zmo): This is temporary for debugging crbug.com/393331.
   // We should remove it afterwards.
   std::string GetStatesForDebugging() const;
@@ -321,6 +323,7 @@ class CC_EXPORT SchedulerStateMachine {
   bool skip_begin_main_frame_to_reduce_latency_;
   bool continuous_painting_;
   bool impl_latency_takes_priority_on_battery_;
+  bool defer_commits_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SchedulerStateMachine);