Add the button style for combobox

ui/views/controls/focusable_border.h

Index: ui/views/controls/focusable_border.h
diff --git a/ui/views/controls/focusable_border.h b/ui/views/controls/focusable_border.h
index 18b7583385caecad66c2d55082872703711ac371..1b97348b7e4232027448725d4c64dbbfeac5d2a1 100644
--- a/ui/views/controls/focusable_border.h
+++ b/ui/views/controls/focusable_border.h
@@ -22,6 +22,9 @@ class VIEWS_EXPORT FocusableBorder : public Border {
  public:
   FocusableBorder();
 
+  // Resets the insets of the border.
+  void ResetInsets();

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

I don't want to add anything more to this class. Can you recreate the border if
you need to?

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

Done.

+
   // Sets the insets of the border.
   void SetInsets(int top, int left, int bottom, int right);