Standardize usage of virtual/override/final in extensions/

extensions/common/features/base_feature_provider.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 EXTENSIONS_COMMON_FEATURES_BASE_FEATURE_PROVIDER_H_
 #define EXTENSIONS_COMMON_FEATURES_BASE_FEATURE_PROVIDER_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/memory/linked_ptr.h"
 #include "base/values.h"
 #include "extensions/common/features/feature_provider.h"
 #include "extensions/common/features/simple_feature.h"
 
 namespace extensions {
 
 // Reads Features out of a simple JSON file description.
 class BaseFeatureProvider : public FeatureProvider {
  public:
   typedef SimpleFeature*(*FeatureFactory)();
 
   // Creates a new BaseFeatureProvider. Pass null to |factory| to have the
   // provider create plain old Feature instances.
   BaseFeatureProvider(const base::DictionaryValue& root,
                       FeatureFactory factory);
-  virtual ~BaseFeatureProvider();
+  ~BaseFeatureProvider() override;
 
   // Gets the feature |feature_name|, if it exists.
-  virtual Feature* GetFeature(const std::string& feature_name) const override;
-  virtual Feature* GetParent(Feature* feature) const override;
-  virtual std::vector<Feature*> GetChildren(const Feature& parent) const
-      override;
+  Feature* GetFeature(const std::string& feature_name) const override;
+  Feature* GetParent(Feature* feature) const override;
+  std::vector<Feature*> GetChildren(const Feature& parent) const override;
 
-  virtual const std::vector<std::string>& GetAllFeatureNames() const override;
+  const std::vector<std::string>& GetAllFeatureNames() const override;
 
  private:
   typedef std::map<std::string, linked_ptr<Feature> > FeatureMap;
   FeatureMap features_;
 
   // Populated on first use.
   mutable std::vector<std::string> feature_names_;
 
   FeatureFactory factory_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_FEATURES_BASE_FEATURE_PROVIDER_H_