Standardize usage of virtual/override/final in mojo/

mojo/shell/context.h

 // Copyright 2013 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_SHELL_CONTEXT_H_
 #define MOJO_SHELL_CONTEXT_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 11 matching lines @@
 
 namespace shell {
 
 class DynamicApplicationLoader;
 class ExternalApplicationListener;
 
 // The "global" context for the shell's main process.
 class Context : ApplicationManager::Delegate {
  public:
   Context();
-  virtual ~Context();
+  ~Context() override;
 
   void Init();
 
   // ApplicationManager::Delegate override.
-  virtual void OnApplicationError(const GURL& gurl) override;
+  void OnApplicationError(const GURL& gurl) override;
 
   void Run(const GURL& url);
   ScopedMessagePipeHandle ConnectToServiceByName(
       const GURL& application_url,
       const std::string& service_name);
 
   TaskRunners* task_runners() { return task_runners_.get(); }
   ApplicationManager* application_manager() { return &application_manager_; }
   MojoURLResolver* mojo_url_resolver() { return &mojo_url_resolver_; }
 
@@ skipping 15 matching lines @@
   base::MessageLoop* ui_loop_;
 #endif  // defined(OS_ANDROID)
 
   DISALLOW_COPY_AND_ASSIGN(Context);
 };
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_CONTEXT_H_