Standardize usage of virtual/override/final specifiers.

ui/views/linux_ui/linux_ui.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 UI_VIEWS_LINUX_UI_LINUX_UI_H_
 #define UI_VIEWS_LINUX_UI_LINUX_UI_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 45 matching lines @@
   enum NonClientMiddleClickAction {
     MIDDLE_CLICK_ACTION_NONE,
     MIDDLE_CLICK_ACTION_LOWER,
     MIDDLE_CLICK_ACTION_MINIMIZE,
     MIDDLE_CLICK_ACTION_TOGGLE_MAXIMIZE
   };
 
   typedef base::Callback<ui::NativeTheme*(aura::Window* window)>
       NativeThemeGetter;
 
-  virtual ~LinuxUI() {}
+  ~LinuxUI() override {}
 
   // Sets the dynamically loaded singleton that draws the desktop native UI.
   static void SetInstance(LinuxUI* instance);
 
   // Returns a LinuxUI instance for the toolkit used in the user's desktop
   // environment.
   //
   // Can return NULL, in case no toolkit has been set. (For example, if we're
   // running with the "--ash" flag.)
   static LinuxUI* instance();
@@ skipping 71 matching lines @@
   // Notifies the window manager that start up has completed.
   // Normally Chromium opens a new window on startup and GTK does this
   // automatically. In case Chromium does not open a new window on startup,
   // e.g. an existing browser window already exists, this should be called.
   virtual void NotifyWindowManagerStartupComplete() = 0;
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_LINUX_UI_LINUX_UI_H_