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

content/renderer/pepper/mock_resource.h

 // Copyright (c) 2012 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 CONTENT_RENDERER_PEPPER_MOCK_RESOURCE_H_
 #define CONTENT_RENDERER_PEPPER_MOCK_RESOURCE_H_
 
 #include "ppapi/shared_impl/resource.h"
 
 namespace content {
 
 // Tests can derive from this to implement special test-specific resources.
 // It's assumed that a test will only need one mock resource, so it can
 // static_cast to get its own implementation.
 class MockResource : public ppapi::Resource {
  public:
   MockResource(PP_Instance instance)
       : Resource(ppapi::OBJECT_IS_IMPL, instance) {}
 
  private:
-  virtual ~MockResource() {}
+  ~MockResource() override {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_MOCK_RESOURCE_H_