Standardize usage of virtual/override/final in cc/

cc/scheduler/scheduler.h

Index: cc/scheduler/scheduler.h
diff --git a/cc/scheduler/scheduler.h b/cc/scheduler/scheduler.h
index 6da951ca2bad7d980599d76efe71b9bae1cd4130..f470d17a9e7faa19a53ccacf92ce49e9ca3a2b2b 100644
--- a/cc/scheduler/scheduler.h
+++ b/cc/scheduler/scheduler.h
@@ -91,10 +91,10 @@ class CC_EXPORT Scheduler : public BeginFrameObserverMixIn,
                                          &frame_sources_constructor));
   }
 
-  virtual ~Scheduler();
+  ~Scheduler() override;
 
   // base::PowerObserver method.
-  virtual void OnPowerStateChange(bool on_battery_power) override;
+  void OnPowerStateChange(bool on_battery_power) override;
 
   const SchedulerSettings& settings() const { return settings_; }
 
@@ -158,14 +158,14 @@ class CC_EXPORT Scheduler : public BeginFrameObserverMixIn,
   base::TimeTicks LastBeginImplFrameTime();
 
   scoped_refptr<base::debug::ConvertableToTraceFormat> AsValue() const;
-  virtual void AsValueInto(base::debug::TracedValue* value) const override;
+  void AsValueInto(base::debug::TracedValue* value) const override;
 
   void SetContinuousPainting(bool continuous_painting) {
     state_machine_.SetContinuousPainting(continuous_painting);
   }
 
   // BeginFrameObserverMixin
-  virtual bool OnBeginFrameMixInDelegate(const BeginFrameArgs& args) override;
+  bool OnBeginFrameMixInDelegate(const BeginFrameArgs& args) override;
 
  protected:
   Scheduler(SchedulerClient* client,