Standardize usage of virtual/override/final in cc/

cc/blink/web_layer_impl.cc

Index: cc/blink/web_layer_impl.cc
diff --git a/cc/blink/web_layer_impl.cc b/cc/blink/web_layer_impl.cc
index b4b9f29aad7e65e6d1eb4738d535e0d2210e4cde..f73ae10429e1174f3c2dc83bd41be82bb1b158f3 100644
--- a/cc/blink/web_layer_impl.cc
+++ b/cc/blink/web_layer_impl.cc
@@ -435,7 +435,7 @@ class TracedDebugInfo : public base::debug::ConvertableToTraceFormat {
   // This object takes ownership of the debug_info object.
   explicit TracedDebugInfo(blink::WebGraphicsLayerDebugInfo* debug_info)
       : debug_info_(debug_info) {}
-  virtual void AppendAsTraceFormat(std::string* out) const override {
+  void AppendAsTraceFormat(std::string* out) const override {
     DCHECK(thread_checker_.CalledOnValidThread());
     blink::WebString web_string;
     debug_info_->appendAsTraceFormat(&web_string);
@@ -443,7 +443,7 @@ class TracedDebugInfo : public base::debug::ConvertableToTraceFormat {
   }
 
  private:
-  virtual ~TracedDebugInfo() {}
+  ~TracedDebugInfo() override {}
   scoped_ptr<blink::WebGraphicsLayerDebugInfo> debug_info_;
   base::ThreadChecker thread_checker_;
 };