Revert of 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 aa153c6bddcaee0bceb6af5c0656ad33d0f81a1a..9dc7817d473c9ad6ee1c719746ca0dd2293238cd 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -258,8 +258,6 @@
     impl_latency_takes_priority_on_battery_ =
         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.
@@ -343,7 +341,6 @@
   bool continuous_painting_;
   bool impl_latency_takes_priority_on_battery_;
   bool children_need_begin_frames_;
-  bool defer_commits_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SchedulerStateMachine);