Compile fix for r173417.

ash/launcher/launcher.h

 // Copyright (c) 2012 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 ASH_LAUNCHER_LAUNCHER_H_
 #define ASH_LAUNCHER_LAUNCHER_H_
 
 #include "ash/ash_export.h"
 #include "ash/launcher/background_animator.h"
 #include "ash/launcher/launcher_types.h"
@@ skipping 112 matching lines @@
 
   views::Widget* GetDimmerWidgetForTest() { return dimmer_.get(); }
 
   aura::Window* window_container() { return window_container_; }
 
   // Called by the activation delegate, before the launcher is activated
   // when no other windows are visible.
   void WillActivateAsFallback() { activating_as_fallback_ = true; }
 
   // Overridden from views::WidgetObserver:
-  void OnWidgetActivationChanged(views::Widget* widget, bool active) OVERRIDE;
+  virtual void OnWidgetActivationChanged(views::Widget* widget,
+                                         bool active) OVERRIDE;
 
  private:
   class DelegateView;
 
   // Widget hosting the view.
   scoped_ptr<views::Widget> widget_;
   scoped_ptr<views::Widget> dimmer_;
 
   aura::Window* window_container_;
 
@@ skipping 15 matching lines @@
 
   // Used then activation is forced from the activation delegate.
   bool activating_as_fallback_;
 
   DISALLOW_COPY_AND_ASSIGN(Launcher);
 };
 
 }  // namespace ash
 
 #endif  // ASH_LAUNCHER_LAUNCHER_H_