Standardize usage of virtual/override/final in cc/

cc/layers/surface_layer.h

Index: cc/layers/surface_layer.h
diff --git a/cc/layers/surface_layer.h b/cc/layers/surface_layer.h
index eace365b91b1a343f3c03334059ebf39f47a9b5d..0b886ebe2c98c780f70db2b1cbd2ce3aac426e1e 100644
--- a/cc/layers/surface_layer.h
+++ b/cc/layers/surface_layer.h
@@ -20,16 +20,15 @@ class CC_EXPORT SurfaceLayer : public Layer {
   void SetSurfaceId(SurfaceId surface_id);
 
   // Layer overrides.
-  virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
-      override;
-  virtual void PushPropertiesTo(LayerImpl* layer) override;
+  scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
+  void PushPropertiesTo(LayerImpl* layer) override;
 
  protected:
   SurfaceLayer();
-  virtual bool HasDrawableContent() const override;
+  bool HasDrawableContent() const override;
 
  private:
-  virtual ~SurfaceLayer();
+  ~SurfaceLayer() override;
 
   SurfaceId surface_id_;