Adds a gfx_export.h to ui/gfx and converts all code in ui/gfx to

ui/gfx/gtk_preserve_window.h

 // 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.
 
 #ifndef UI_GFX_GTK_PRESERVE_WINDOW_H_
 #define UI_GFX_GTK_PRESERVE_WINDOW_H_
 
 #include <atk/atk.h>
 #include <gdk/gdk.h>
 #include <gtk/gtk.h>
 
-#include "ui/base/ui_export.h"
+#include "ui/gfx/gfx_export.h"
 
 // GtkFixed creates an X window when realized and destroys an X window
 // when unrealized. GtkPreserveWindow allows overrides this
 // behaviour. When preserve is set (via gtk_preserve_window_set_preserve),
 // the X window is only destroyed when the widget is destroyed.
 
 G_BEGIN_DECLS
 
 #define GTK_TYPE_PRESERVE_WINDOW                                 \
     (gtk_preserve_window_get_type())
@@ skipping 42 matching lines @@
 // are made on this widget. The parameter |userdata| will be passed to the
 // factory function.
 UI_EXPORT void gtk_preserve_window_set_accessible_factory(
     GtkPreserveWindow* widget,
     AtkObject* (*factory)(void* userdata),
     gpointer userdata);
 
 G_END_DECLS
 
 #endif  // UI_GFX_GTK_PRESERVE_WINDOW_H_