aura: Make aura::TooltipClient completely static?

ui/aura/client/tooltip_client.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 UI_AURA_CLIENT_TOOLTIP_CLIENT_H_
 #define UI_AURA_CLIENT_TOOLTIP_CLIENT_H_
 #pragma once
 
 #include "ui/aura/aura_export.h"
 #include "ui/aura/event.h"
 #include "ui/gfx/font.h"
 
 namespace aura {
 
 class Window;
 
 class AURA_EXPORT TooltipClient {
  public:
   // Returns the default font used by tooltips.
   static gfx::Font GetDefaultFont();
 
   // Returns the maximum width of the tooltip. |x| and |y| give the location
   // the tooltip is to be displayed on in screen coordinates.
   static int GetMaxWidth(int x, int y);
 
   // Informs the shell tooltip manager of change in tooltip for window |target|.
-  virtual void UpdateTooltip(Window* target) = 0;
+  static void UpdateTooltip(Window* target);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_CLIENT_TOOLTIP_CLIENT_H_