Standardize usage of virtual/override/final in chrome/

chrome/common/extensions/api/file_browser_handlers/file_browser_handler.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 CHROME_COMMON_EXTENSIONS_API_FILE_BROWSER_HANDLERS_FILE_BROWSER_HANDLER_H_
 #define CHROME_COMMON_EXTENSIONS_API_FILE_BROWSER_HANDLERS_FILE_BROWSER_HANDLER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 71 matching lines @@
   unsigned int file_access_permission_flags_;
 
   // A list of file filters.
   extensions::URLPatternSet url_set_;
 };
 
 // Parses the "file_browser_handlers" extension manifest key.
 class FileBrowserHandlerParser : public extensions::ManifestHandler {
  public:
   FileBrowserHandlerParser();
-  virtual ~FileBrowserHandlerParser();
+  ~FileBrowserHandlerParser() override;
 
-  virtual bool Parse(extensions::Extension* extension,
-                     base::string16* error) override;
+  bool Parse(extensions::Extension* extension, base::string16* error) override;
 
  private:
-  virtual const std::vector<std::string> Keys() const override;
+  const std::vector<std::string> Keys() const override;
 };
 
 #endif  // CHROME_COMMON_EXTENSIONS_API_FILE_BROWSER_HANDLERS_FILE_BROWSER_HANDLER_H_