Standardize usage of virtual/override/final in mojo/

mojo/application_manager/application_loader.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_APPLICATION_MANAGER_APPLICATION_LOADER_H_
 #define MOJO_APPLICATION_MANAGER_APPLICATION_LOADER_H_
 
 #include "base/memory/ref_counted.h"
 #include "mojo/application_manager/application_manager_export.h"
 #include "mojo/public/cpp/system/core.h"
@@ skipping 29 matching lines @@
     friend base::RefCounted<LoadCallbacks>;
     virtual ~LoadCallbacks() {}
   };
 
   // Implements RegisterApplication() by returning a handle that was specified
   // at construction time. LoadWithContentHandler() is not supported.
   class MOJO_APPLICATION_MANAGER_EXPORT SimpleLoadCallbacks
       : public LoadCallbacks {
    public:
     SimpleLoadCallbacks(ScopedMessagePipeHandle shell_handle);
-    virtual ScopedMessagePipeHandle RegisterApplication() override;
-    virtual void LoadWithContentHandler(const GURL& content_handler_url,
-                                        URLResponsePtr response) override;
+    ScopedMessagePipeHandle RegisterApplication() override;
+    void LoadWithContentHandler(const GURL& content_handler_url,
+                                URLResponsePtr response) override;
 
    private:
     ScopedMessagePipeHandle shell_handle_;
-    virtual ~SimpleLoadCallbacks();
+    ~SimpleLoadCallbacks() override;
   };
 
   virtual ~ApplicationLoader() {}
 
   // Load the application named |url|. Applications can be loaded two ways:
   //
   // 1. |url| can refer directly to a Mojo application. In this case, call
   //    callbacks->RegisterApplication(). The returned handle should be used to
   //    implement the mojo.Application interface. Note that the returned handle
   //    can be invalid in the case where the application has already been
@@ skipping 12 matching lines @@
   virtual void OnApplicationError(ApplicationManager* manager,
                                   const GURL& url) = 0;
 
  protected:
   ApplicationLoader() {}
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_APPLICATION_MANAGER_APPLICATION_LOADER_H_