Fixes leak of NativeTextfieldWin. The underlying HWND was getting

ui/views/controls/textfield/native_textfield_win.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 UI_VIEWS_CONTROLS_TEXTFIELD_NATIVE_TEXTFIELD_WIN_H_
 #define UI_VIEWS_CONTROLS_TEXTFIELD_NATIVE_TEXTFIELD_WIN_H_
 
 #include <atlbase.h>
 #include <atlapp.h>
 #include <atlcrack.h>
@@ skipping 201 matching lines @@
   LRESULT OnMouseWheel(UINT message, WPARAM w_param, LPARAM l_param);
   void OnMouseMove(UINT keys, const CPoint& point);
   int OnNCCalcSize(BOOL w_param, LPARAM l_param);
   void OnNCPaint(HRGN region);
   void OnNonLButtonDown(UINT keys, const CPoint& point);
   void OnPaste();
   void OnSetFocus(HWND hwnd);
   void OnKillFocus(HWND hwnd);
   void OnSysChar(TCHAR ch, UINT repeat_count, UINT flags);
 
+  // CWindowImpl overrides:
+  virtual void OnFinalMessage(HWND hwnd) OVERRIDE;
+
   // Helper function for OnChar() and OnKeyDown() that handles keystrokes that
   // could change the text in the edit.
   // Note: This function assumes GetCurrentMessage() returns a MSG with
   // msg > WM_KEYFIRST and < WM_KEYLAST.
   void HandleKeystroke();
 
   // Every piece of code that can change the edit should call these functions
   // before and after the change.  These functions determine if anything
   // meaningful changed, and do any necessary updating and notification.
   void OnBeforePossibleChange();
@@ skipping 83 matching lines @@
   int accessibility_state_;
 
   scoped_ptr<ui::TSFEventRouter> tsf_event_router_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeTextfieldWin);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_TEXTFIELD_NATIVE_TEXTFIELD_WIN_H_