Standardize usage of virtual/override/final in extensions/

extensions/browser/api/system_info/system_info_api.cc

 // 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.
 
 #include "extensions/browser/api/system_info/system_info_api.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
@@ skipping 35 matching lines @@
 }
 
 // Event router for systemInfo API. It is a singleton instance shared by
 // multiple profiles.
 class SystemInfoEventRouter : public gfx::DisplayObserver,
                               public storage_monitor::RemovableStorageObserver {
  public:
   static SystemInfoEventRouter* GetInstance();
 
   SystemInfoEventRouter();
-  virtual ~SystemInfoEventRouter();
+  ~SystemInfoEventRouter() override;
 
   // Add/remove event listener for the |event_name| event.
   void AddEventListener(const std::string& event_name);
   void RemoveEventListener(const std::string& event_name);
 
  private:
   // gfx::DisplayObserver:
-  virtual void OnDisplayAdded(const gfx::Display& new_display) override;
-  virtual void OnDisplayRemoved(const gfx::Display& old_display) override;
-  virtual void OnDisplayMetricsChanged(const gfx::Display& display,
-                                       uint32_t metrics) override;
+  void OnDisplayAdded(const gfx::Display& new_display) override;
+  void OnDisplayRemoved(const gfx::Display& old_display) override;
+  void OnDisplayMetricsChanged(const gfx::Display& display,
+                               uint32_t metrics) override;
 
   // RemovableStorageObserver implementation.
-  virtual void OnRemovableStorageAttached(
+  void OnRemovableStorageAttached(
       const storage_monitor::StorageInfo& info) override;
-  virtual void OnRemovableStorageDetached(
+  void OnRemovableStorageDetached(
       const storage_monitor::StorageInfo& info) override;
 
   // Called from any thread to dispatch the systemInfo event to all extension
   // processes cross multiple profiles.
   void DispatchEvent(const std::string& event_name,
                      scoped_ptr<base::ListValue> args);
 
   // Called to dispatch the systemInfo.display.onDisplayChanged event.
   void OnDisplayChanged();
 
@@ skipping 170 matching lines @@
 void SystemInfoAPI::OnListenerRemoved(const EventListenerInfo& details) {
   if (IsSystemStorageEvent(details.event_name)) {
     StorageMonitor::GetInstance()->EnsureInitialized(
         base::Bind(&RemoveEventListener, details.event_name));
   } else {
     RemoveEventListener(details.event_name);
   }
 }
 
 }  // namespace extensions