WinAura: don't create tooltip on hide

ui/views/corewm/tooltip_win.cc

 // Copyright 2013 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/corewm/tooltip_win.h"
 
 #include <winuser.h>
 
 #include "base/debug/stack_trace.h"
 #include "base/i18n/rtl.h"
@@ skipping 116 matching lines @@
   if (!EnsureTooltipWindow())
     return;
 
   SendMessage(tooltip_hwnd_, TTM_TRACKACTIVATE,
               TRUE, reinterpret_cast<LPARAM>(&toolinfo_));
   SetWindowPos(tooltip_hwnd_, HWND_TOPMOST, 0, 0, 0, 0,
                SWP_NOACTIVATE | SWP_NOMOVE | SWP_NOOWNERZORDER | SWP_NOSIZE);
 }
 
 void TooltipWin::Hide() {
-  if (!EnsureTooltipWindow())
+  if (!tooltip_hwnd_)
     return;
 
   SendMessage(tooltip_hwnd_, TTM_TRACKACTIVATE, FALSE,
               reinterpret_cast<LPARAM>(&toolinfo_));
 }
 
 bool TooltipWin::IsVisible() {
   return showing_;
 }
 
 }  // namespace corewm
 }  // namespace views