Add the button style for combobox

ui/views/painter.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_VIEWS_PAINTER_H_
 #define UI_VIEWS_PAINTER_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/views/views_export.h"
 
 namespace gfx {
 class Canvas;
 class ImageSkia;
 class Insets;
 class Rect;
 class Size;
 }
 
 // A macro to define arrays of IDR constants used with CreateImageGridPainter.
 #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, }
 
+#define IMAGE_GRID2(x, y) { \

[sky, 2013/12/02 21:28:55]

Why do you need a new macro for this? Can't you embed the y in the name, eg
IDR_COMBOBOX_BUTTON_BOTTOM_H and IDR_COMBOBOX_BUTTON_BOTTOM_P ?

[hajimehoshi, 2013/12/03 10:30:52]

Done.

+    x ## _TOP_LEFT_ ## y,    x ## _TOP_ ## y,    x ## _TOP_RIGHT_ ## y, \
+    x ## _LEFT_ ## y,        x ## _CENTER_ ## y, x ## _RIGHT_ ## y, \
+    x ## _BOTTOM_LEFT_ ## y, x ## _BOTTOM_ ## y, x ## _BOTTOM_RIGHT_ ## y, }
+
 namespace views {
 
 // Painter, as the name implies, is responsible for painting in a particular
 // region. Think of Painter as a Border or Background that can be painted
 // in any region of a View.
 class VIEWS_EXPORT Painter {
  public:
   Painter();
   virtual ~Painter();
 
@@ skipping 65 matching lines @@
 
   // NOTE: the images are owned by ResourceBundle. Don't free them.
   const gfx::ImageSkia* images_[3];
 
   DISALLOW_COPY_AND_ASSIGN(HorizontalPainter);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_PAINTER_H_