Standardize usage of virtual/override/final in chrome/

chrome/common/extensions/manifest_handlers/content_scripts_handler.h

 // Copyright (c) 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 CHROME_COMMON_EXTENSIONS_MANIFEST_HANDLERS_CONTENT_SCRIPTS_HANDLER_H_
 #define CHROME_COMMON_EXTENSIONS_MANIFEST_HANDLERS_CONTENT_SCRIPTS_HANDLER_H_
 
 #include <string>
 
 #include "extensions/common/extension.h"
 #include "extensions/common/manifest_handler.h"
 #include "extensions/common/user_script.h"
 
 namespace extensions {
 
 class URLPatternSet;
 
 struct ContentScriptsInfo : public Extension::ManifestData {
   ContentScriptsInfo();
-  virtual ~ContentScriptsInfo();
+  ~ContentScriptsInfo() override;
 
   // Paths to the content scripts the extension contains (possibly empty).
   UserScriptList content_scripts;
 
   // Returns the content scripts for the extension (if the extension has
   // no content scripts, this returns an empty list).
   static const UserScriptList& GetContentScripts(const Extension* extension);
 
   // Returns the list of hosts that this extension can run content scripts on.
   static URLPatternSet GetScriptableHosts(const Extension* extension);
 
   // Returns true if the extension has a content script declared at |url|.
   static bool ExtensionHasScriptAtURL(const Extension* extension,
                                       const GURL& url);
 };
 
 // Parses the "content_scripts" manifest key.
 class ContentScriptsHandler : public ManifestHandler {
  public:
   ContentScriptsHandler();
-  virtual ~ContentScriptsHandler();
+  ~ContentScriptsHandler() override;
 
-  virtual bool Parse(Extension* extension, base::string16* error) override;
-  virtual bool Validate(const Extension* extension,
-                        std::string* error,
-                        std::vector<InstallWarning>* warnings) const override;
+  bool Parse(Extension* extension, base::string16* error) override;
+  bool Validate(const Extension* extension,
+                std::string* error,
+                std::vector<InstallWarning>* warnings) const override;
 
  private:
-  virtual const std::vector<std::string> Keys() const override;
+  const std::vector<std::string> Keys() const override;
 
   DISALLOW_COPY_AND_ASSIGN(ContentScriptsHandler);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_MANIFEST_HANDLERS_CONTENT_SCRIPTS_HANDLER_H_