Make aura_demo work on Mac

ui/base/view_prop.h

 // Copyright (c) 2011 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_BASE_VIEW_PROP_H_
 #define UI_BASE_VIEW_PROP_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "ui/base/ui_base_export.h"
 #include "ui/gfx/native_widget_types.h"
 
-#if defined(OS_MACOSX) || (defined(OS_LINUX) && !defined(USE_AURA))
+#if !defined(OS_WIN) && !defined(USE_AURA)
 #error view_prop.h is only for windows and aura builds.
 #endif
 
 namespace ui {
 
 // ViewProp maintains a key/value pair for a particular view. ViewProp is
 // designed as a replacement for the Win32's SetProp, but does not make use of
 // window manager memory. ViewProp shares similar semantics as SetProp, the
 // value for a particular view/key pair comes from the last ViewProp created.
 class UI_BASE_EXPORT ViewProp {
@@ skipping 18 matching lines @@
 
   // Stores the actual data.
   scoped_refptr<Data> data_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewProp);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_VIEW_PROP_H_