Standardize usage of virtual/override/final in content/

content/public/renderer/render_view_observer.h

Index: content/public/renderer/render_view_observer.h
diff --git a/content/public/renderer/render_view_observer.h b/content/public/renderer/render_view_observer.h
index a0dd80bf80e070154ddc2ab93ecbb4b336af5b17..4c7aba0529f4b275e4dcbb1e4e755fd690407832 100644
--- a/content/public/renderer/render_view_observer.h
+++ b/content/public/renderer/render_view_observer.h
@@ -98,17 +98,17 @@ class CONTENT_EXPORT RenderViewObserver : public IPC::Listener,
   virtual void OnStop() {}
 
   // IPC::Listener implementation.
-  virtual bool OnMessageReceived(const IPC::Message& message) override;
+  bool OnMessageReceived(const IPC::Message& message) override;
 
   // IPC::Sender implementation.
-  virtual bool Send(IPC::Message* message) override;
+  bool Send(IPC::Message* message) override;
 
   RenderView* render_view() const;
   int routing_id() const { return routing_id_; }
 
  protected:
   explicit RenderViewObserver(RenderView* render_view);
-  virtual ~RenderViewObserver();
+  ~RenderViewObserver() override;
 
   // Sets |render_view_| to track.
   // Removes itself of previous (if any) |render_view_| observer list and adds