Standardize usage of virtual/override/final in mojo/

mojo/apps/js/application_delegate_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_APPS_JS_CONTENT_HANDLER_H_
 #define MOJO_APPS_JS_CONTENT_HANDLER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "mojo/public/cpp/application/application_delegate.h"
@@ skipping 11 matching lines @@
 // Manages the JSApps started by this content handler. This class owns the one
 // reference to the Mojo shell. JSApps post a task to the content handler's
 // thread to connect to a service or to quit.
 //
 // The lifetime each JSApp is defined by its entry in AppVector. When the entry
 // is removed ("erased") by QuitJSApp(), the JSApp is destroyed.
 
 class ApplicationDelegateImpl : public ApplicationDelegate {
  public:
   ApplicationDelegateImpl();
-  virtual ~ApplicationDelegateImpl();
+  ~ApplicationDelegateImpl() override;
 
   // Add app to the AppVector and call its Start() method.
   void StartJSApp(scoped_ptr<JSApp> app);
 
   // Remove app from the AppVector; destroys the app.
   void QuitJSApp(JSApp *app);
 
   void ConnectToService(ScopedMessagePipeHandle pipe_handle,
                         const std::string& application_url,
                         const std::string& interface_name);
 
  protected:
   // ApplicationDelegate:
-  virtual void Initialize(ApplicationImpl* app) override;
+  void Initialize(ApplicationImpl* app) override;
 
  private:
   typedef ScopedVector<JSApp> AppVector;
   ApplicationImpl* application_impl_;
   AppVector app_vector_;
 };
 
 }  // namespace apps
 }  // namespace mojo
 
 #endif  // MOJO_APPS_JS_CONTENT_HANDLER_H_