Standardize usage of virtual/override/final in chrome/renderer/

chrome/renderer/chrome_render_frame_observer.h

Index: chrome/renderer/chrome_render_frame_observer.h
diff --git a/chrome/renderer/chrome_render_frame_observer.h b/chrome/renderer/chrome_render_frame_observer.h
index 2dfb24776e8b8d794f06dec2b37bb259c18f3758..6fdc785c2ef8dbc1c12d3fd2b8adb89a513fbf2e 100644
--- a/chrome/renderer/chrome_render_frame_observer.h
+++ b/chrome/renderer/chrome_render_frame_observer.h
@@ -17,11 +17,11 @@ class Size;
 class ChromeRenderFrameObserver : public content::RenderFrameObserver {
  public:
   explicit ChromeRenderFrameObserver(content::RenderFrame* render_frame);
-  virtual ~ChromeRenderFrameObserver();
+  ~ChromeRenderFrameObserver() override;
 
  private:
   // RenderFrameObserver implementation.
-  virtual bool OnMessageReceived(const IPC::Message& message) override;
+  bool OnMessageReceived(const IPC::Message& message) override;
 
   // IPC handlers
   void OnSetIsPrerendering(bool is_prerendering);