Fix HWNDMessageHandler::OnSetCursor handling of HTERROR.

ui/views/win/hwnd_message_handler.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/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <oleacc.h>
 #include <shellapi.h>
 #include <wtsapi32.h>
@@ skipping 1923 matching lines @@
     case HTBOTTOMRIGHT:
       cursor = IDC_SIZENWSE;
       break;
     case HTTOPRIGHT:
     case HTBOTTOMLEFT:
       cursor = IDC_SIZENESW;
       break;
     case HTCLIENT:
       SetCursor(current_cursor_);
       return 1;
+    case LOWORD(HTERROR):  // Use HTERROR's LOWORD value for valid comparison.
+      SetMsgHandled(FALSE);
+      break;
     default:
       // Use the default value, IDC_ARROW.
       break;
   }
   ::SetCursor(LoadCursor(NULL, cursor));
   return 1;
 }
 
 void HWNDMessageHandler::OnSetFocus(HWND last_focused_window) {
   delegate_->HandleNativeFocus(last_focused_window);
@@ skipping 456 matching lines @@
     POINT cursor_pos = {0};
     ::GetCursorPos(&cursor_pos);
     if (memcmp(&cursor_pos, &mouse_location, sizeof(POINT)))
       return false;
     return true;
   }
   return false;
 }
 
 }  // namespace views