Fixes leak of NativeTextfieldWin. The underlying HWND was getting

ui/views/controls/textfield/native_textfield_win.cc

 // 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.
 
 #include "ui/views/controls/textfield/native_textfield_win.h"
 
 #include <algorithm>
 
 #include "base/i18n/case_conversion.h"
 #include "base/i18n/rtl.h"
@@ skipping 1066 matching lines @@
   // useful, so we discard most.  Exceptions:
   //   * ctrl-alt-<xxx>, which is sometimes important, generates WM_CHAR instead
   //     of WM_SYSCHAR, so it doesn't need to be handled here.
   //   * alt-space gets translated by the default WM_SYSCHAR handler to a
   //     WM_SYSCOMMAND to open the application context menu, so we need to allow
   //     it through.
   if (ch == VK_SPACE)
     SetMsgHandled(false);
 }
 
+void NativeTextfieldWin::OnFinalMessage(HWND hwnd) {
+  delete this;
+}
+
 void NativeTextfieldWin::HandleKeystroke() {
   const MSG* msg = GetCurrentMessage();
   ScopedFreeze freeze(this, GetTextObjectModel());
 
   TextfieldController* controller = textfield_->GetController();
   bool handled = false;
   if (controller) {
     ui::KeyEvent event(*msg, msg->message == WM_CHAR);
     handled = controller->HandleKeyEvent(textfield_, event);
   }
@@ skipping 178 matching lines @@
   context_menu_contents_->AddSeparator(ui::NORMAL_SEPARATOR);
   context_menu_contents_->AddItemWithStringId(IDS_APP_CUT, IDS_APP_CUT);
   context_menu_contents_->AddItemWithStringId(IDS_APP_COPY, IDS_APP_COPY);
   context_menu_contents_->AddItemWithStringId(IDS_APP_PASTE, IDS_APP_PASTE);
   context_menu_contents_->AddSeparator(ui::NORMAL_SEPARATOR);
   context_menu_contents_->AddItemWithStringId(IDS_APP_SELECT_ALL,
                                               IDS_APP_SELECT_ALL);
 }
 
 }  // namespace views