Standardize usage of virtual/override/final in chrome/browser/extensions/

chrome/browser/extensions/active_install_data.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 CHROME_BROWSER_EXTENSIONS_ACTIVE_INSTALL_DATA_H_
 #define CHROME_BROWSER_EXTENSIONS_ACTIVE_INSTALL_DATA_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 20 matching lines @@
 class ScopedActiveInstall : public InstallObserver {
  public:
   // This constructor registers an active install with the InstallTracker.
   ScopedActiveInstall(InstallTracker* tracker,
                       const ActiveInstallData& install_data);
 
   // This constructor does not register an active install. The extension install
   // is still deregistered upon destruction.
   ScopedActiveInstall(InstallTracker* tracker, const std::string& extension_id);
 
-  virtual ~ScopedActiveInstall();
+  ~ScopedActiveInstall() override;
 
   // Ensures that the active install is not deregistered upon destruction. This
   // may be necessary if the extension install outlives the lifetime of this
   // instance.
   void CancelDeregister();
 
  private:
   void Init();
 
   // InstallObserver implementation.
-  virtual void OnShutdown() override;
+  void OnShutdown() override;
 
   InstallTracker* tracker_;
   ScopedObserver<InstallTracker, InstallObserver> tracker_observer_;
   std::string extension_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedActiveInstall);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_ACTIVE_INSTALL_DATA_H_