Makes native_widget_types forward declare ui::Cursor.

ui/base/cursor/cursor_loader_win.cc

Index: ui/base/cursor/cursor_loader_win.cc
diff --git a/ui/base/cursor/cursor_loader_win.cc b/ui/base/cursor/cursor_loader_win.cc
index 9d633f1cec8969859abd553e35385309162b656c..6d35e55457481b2b8ff50da7dba2669c87ed9ca5 100644
--- a/ui/base/cursor/cursor_loader_win.cc
+++ b/ui/base/cursor/cursor_loader_win.cc
@@ -2,11 +2,16 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "ui/base/cursor/cursor_loader_win.h"
+
 #include "base/lazy_instance.h"
 #include "base/strings/string16.h"
-#include "ui/base/cursor/cursor_loader_win.h"
 #include "grit/ui_unscaled_resources.h"
 
+#if defined(USE_AURA)
+#include "ui/base/cursor/cursor.h"
+#endif
+
 namespace ui {
 
 #if defined(USE_AURA)