aura: Make aura::TooltipClient completely static?

ui/aura_shell/shell_tooltip_manager.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_SHELL_SHELL_TOOLTIP_MANAGER_H_
 #define UI_AURA_SHELL_SHELL_TOOLTIP_MANAGER_H_
 #pragma once
 
 #include "base/memory/scoped_ptr.h"
 #include "base/string16.h"
 #include "base/timer.h"
 #include "ui/aura/client/tooltip_client.h"
 #include "ui/aura/event_filter.h"
 #include "ui/aura/window_observer.h"
 #include "ui/aura_shell/aura_shell_export.h"
 #include "ui/gfx/point.h"
 
 namespace aura {
 class KeyEvent;
 class MouseEvent;
 class TouchEvent;
 class Window;
 }
 
 namespace aura_shell {
 
 // ShellTooltipManager provides tooltip functionality for aura shell.
-class AURA_SHELL_EXPORT ShellTooltipManager : public aura::TooltipClient,
-                                              public aura::EventFilter,
+class AURA_SHELL_EXPORT ShellTooltipManager : public aura::EventFilter,
                                               public aura::WindowObserver {
  public:
   ShellTooltipManager();
   virtual ~ShellTooltipManager();
 
-  // Overridden from aura::TooltipClient.
+  // Updates the tooltip for window |target|.
   void UpdateTooltip(aura::Window* target);
 
   // Overridden from aura::EventFilter.
   virtual bool PreHandleKeyEvent(aura::Window* target,
                                  aura::KeyEvent* event) OVERRIDE;
   virtual bool PreHandleMouseEvent(aura::Window* target,
                                    aura::MouseEvent* event) OVERRIDE;
   virtual ui::TouchStatus PreHandleTouchEvent(aura::Window* target,
                                               aura::TouchEvent* event) OVERRIDE;
 
@@ skipping 16 matching lines @@
   base::RepeatingTimer<ShellTooltipManager> tooltip_timer_;
 
   gfx::Point curr_mouse_loc_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellTooltipManager);
 };
 
 }  // namespace aura_shell
 
 #endif  // UI_AURA_SHELL_SHELL_TOOLTIP_MANAGER_H_