Fixes bug where tooltips would get stuck. This was happening because...

chrome/views/tooltip_manager.h

 // Copyright (c) 2006-2008 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_VIEWS_TOOLTIP_MANAGER_H_
 #define CHROME_VIEWS_TOOLTIP_MANAGER_H_
 
 #include <windows.h>
 #include <string>
 #include "base/basictypes.h"
@@ skipping 58 matching lines @@
 
   // Invoked when toolbar icon gets focus.
   void ShowKeyboardTooltip(View* view);
 
   // Invoked when toolbar loses focus.
   void HideKeyboardTooltip();
 
   // Message handlers. These forward to the tooltip control.
   virtual void OnMouse(UINT u_msg, WPARAM w_param, LPARAM l_param);
   LRESULT OnNotify(int w_param, NMHDR* l_param, bool* handled);
+  // Not used directly by TooltipManager, but provided for AeroTooltipManager.
+  virtual void OnMouseLeave() {}
 
  protected:
   virtual void Init();
 
   // Updates the tooltip for the specified location.
   void UpdateTooltip(int x, int y);
 
   // Parent window the tooltip is added to.
   HWND parent_;
 
@@ skipping 65 matching lines @@
   // Used to register DestroyTooltipWindow function with postdelayedtask
   // function.
   ScopedRunnableMethodFactory<TooltipManager> keyboard_tooltip_factory_;
 
   DISALLOW_EVIL_CONSTRUCTORS(TooltipManager);
 };
 
 }  // namespace views
 
 #endif // CHROME_VIEWS_TOOLTIP_MANAGER_H_