C++11 override style change for athena

athena/extensions/shell/athena_shell_app_window_client.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 ATHENA_EXTENSIONS_SHELL_ATHENA_SHELL_APP_WINDOW_CLIENT_H_
 #define ATHENA_EXTENSIONS_SHELL_ATHENA_SHELL_APP_WINDOW_CLIENT_H_
 
 #include "athena/extensions/athena_app_window_client_base.h"
 #include "base/macros.h"
 
 namespace athena {
 
 class AthenaShellAppWindowClient : public AthenaAppWindowClientBase {
  public:
   AthenaShellAppWindowClient();
-  virtual ~AthenaShellAppWindowClient();
+  ~AthenaShellAppWindowClient() override;
 
  private:
   // extensions::AppWindowClient
-  virtual extensions::AppWindow* CreateAppWindow(
+  extensions::AppWindow* CreateAppWindow(
       content::BrowserContext* context,
       const extensions::Extension* extension) override;
-  virtual void OpenDevToolsWindow(content::WebContents* web_contents,
-                                  const base::Closure& callback) override;
-  virtual bool IsCurrentChannelOlderThanDev() override;
+  void OpenDevToolsWindow(content::WebContents* web_contents,
+                          const base::Closure& callback) override;
+  bool IsCurrentChannelOlderThanDev() override;
 
   DISALLOW_COPY_AND_ASSIGN(AthenaShellAppWindowClient);
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_EXTENSIONS_SHELL_ATHENA_SHELL_APP_WINDOW_CLIENT_H_