[OSX] IMAGE_GRID macro for NinePartImage.

ui/base/cocoa/appkit_utils.h

 // 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.
 
 #ifndef UI_BASE_COCOA_APPKIT_UTILS_H
 #define UI_BASE_COCOA_APPKIT_UTILS_H
 
 #import <Cocoa/Cocoa.h>
 
 #include "ui/base/ui_base_export.h"
 
 namespace ui {
 
 struct NinePartImageIds {
   int top_left;
   int top;
   int top_right;
   int left;
   int center;
   int right;
   int bottom_left;
   int bottom;
   int bottom_right;
 };
 
+// A macro to define arrays of IDR constants used with DrawNinePartImage.
+#define IMAGE_GRID(x) { x ## _TOP_LEFT,    x ## _TOP,    x ## _TOP_RIGHT, \
+                        x ## _LEFT,        x ## _CENTER, x ## _RIGHT, \
+                        x ## _BOTTOM_LEFT, x ## _BOTTOM, x ## _BOTTOM_RIGHT, }
+
 // Utility method to draw a nine part image using image ids.
 UI_BASE_EXPORT void DrawNinePartImage(NSRect frame,
                                       const NinePartImageIds& image_ids,
                                       NSCompositingOperation operation,
                                       CGFloat alpha,
                                       BOOL flipped);
 
 }  // namespace ui
 
 #endif  // UI_BASE_COCOA_APPKIT_UTILS_H