Build fix for clang bot.

chrome/browser/chromeos/setting_level_bubble.h

 // Copyright (c) 2011 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_CHROMEOS_SETTING_LEVEL_BUBBLE_H_
 #define CHROME_BROWSER_CHROMEOS_SETTING_LEVEL_BUBBLE_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
@@ skipping 43 matching lines @@
 
   virtual ~SettingLevelBubble();
 
  private:
   FRIEND_TEST_ALL_PREFIXES(SettingLevelBubbleTest, CreateAndUpdate);
   FRIEND_TEST_ALL_PREFIXES(SettingLevelBubbleTest, ShowBubble);
   FRIEND_TEST_ALL_PREFIXES(BrightnessBubbleTest, UpdateWithoutShowing);
   FRIEND_TEST_ALL_PREFIXES(VolumeBubbleTest, GetInstanceAndShow);
 
   // views::Widget::Observer overrides:
-  void OnWidgetClosing(views::Widget* widget) OVERRIDE;
+  virtual void OnWidgetClosing(views::Widget* widget) OVERRIDE;
 
   // Creates the bubble content view.
   // Caller should call Init() on the returned SettingLevelBubbleView.
   SettingLevelBubbleView* CreateView();
 
   // Callback for |hide_timer_|.  Starts fading out.
   void OnHideTimeout();
 
   // Callback for |animation_timer_|.  Updates the level displayed by the view,
   // also stopping the animation if we've reached the target.
@@ skipping 42 matching lines @@
 
   // Is |animation_timer_| currently running?
   bool is_animating_;
 
   DISALLOW_COPY_AND_ASSIGN(SettingLevelBubble);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_SETTING_LEVEL_BUBBLE_H_