Standardize usage of virtual/override/final in cc/

cc/layers/nine_patch_layer.h

Index: cc/layers/nine_patch_layer.h
diff --git a/cc/layers/nine_patch_layer.h b/cc/layers/nine_patch_layer.h
index c1891bc2439c54245a959991386616acd8b8b26d..f5aa712f2437e7f904eeff585bc2a181f38805d2 100644
--- a/cc/layers/nine_patch_layer.h
+++ b/cc/layers/nine_patch_layer.h
@@ -21,7 +21,7 @@ class CC_EXPORT NinePatchLayer : public UIResourceLayer {
  public:
   static scoped_refptr<NinePatchLayer> Create();
 
-  virtual void PushPropertiesTo(LayerImpl* layer) override;
+  void PushPropertiesTo(LayerImpl* layer) override;
 
   // |border| is the space around the center rectangular region in layer space
   // (known as aperture in image space).  |border.x()| and |border.y()| are the
@@ -41,9 +41,8 @@ class CC_EXPORT NinePatchLayer : public UIResourceLayer {
 
  private:
   NinePatchLayer();
-  virtual ~NinePatchLayer();
-  virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
-      override;
+  ~NinePatchLayer() override;
+  scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
 
   gfx::Rect border_;
   bool fill_center_;