[OSX] IMAGE_GRID macro for NinePartImage.

ui/base/cocoa/appkit_utils.h

Index: ui/base/cocoa/appkit_utils.h
diff --git a/ui/base/cocoa/appkit_utils.h b/ui/base/cocoa/appkit_utils.h
index eca3a7ee720779640ba204fc32896ede3f360615..18f1fdfa368a84a7fab6c9454787b3a2dbff65ed 100644
--- a/ui/base/cocoa/appkit_utils.h
+++ b/ui/base/cocoa/appkit_utils.h
@@ -23,6 +23,11 @@ struct NinePartImageIds {
   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,