Standardize usage of virtual/override/final in ui/

ui/compositor/layer.cc

Index: ui/compositor/layer.cc
diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index dd0de4478ed553856908e835701c71a97f6a9786..7a2caf41302ef533a4c9f4c82a41f844dac51e48 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -742,14 +742,14 @@ void Layer::SetForceRenderSurface(bool force) {
 class LayerDebugInfo : public base::debug::ConvertableToTraceFormat {
  public:
   explicit LayerDebugInfo(std::string name) : name_(name) { }
-  virtual void AppendAsTraceFormat(std::string* out) const override {
+  void AppendAsTraceFormat(std::string* out) const override {
     base::DictionaryValue dictionary;
     dictionary.SetString("layer_name", name_);
     base::JSONWriter::Write(&dictionary, out);
   }
 
  private:
-  virtual ~LayerDebugInfo() { }
+  ~LayerDebugInfo() override {}
   std::string name_;
 };