Use a single views::MenuConfig instance for each platform

ui/views/controls/menu/menu_config.h

Index: ui/views/controls/menu/menu_config.h
diff --git a/ui/views/controls/menu/menu_config.h b/ui/views/controls/menu/menu_config.h
index 2a43acab644c42255e1060f3854006c782a4c629..6bbf4e8f4f4d57b51ee72edec021bf99e842c85b 100644
--- a/ui/views/controls/menu/menu_config.h
+++ b/ui/views/controls/menu/menu_config.h
@@ -9,19 +9,15 @@
 #include "ui/gfx/font_list.h"
 #include "ui/views/views_export.h"
 
-namespace ui {
-class NativeTheme;
-}
-
 namespace views {
 
 // Layout type information for menu items. Use the instance() method to obtain
 // the MenuConfig for the current platform.
 struct VIEWS_EXPORT MenuConfig {
-  explicit MenuConfig(const ui::NativeTheme* theme);
+  MenuConfig();
   ~MenuConfig();
 
-  static const MenuConfig& instance(const ui::NativeTheme* theme);
+  static const MenuConfig& instance();
 
   // Font list used by menus.
   gfx::FontList font_list;
@@ -125,10 +121,7 @@ struct VIEWS_EXPORT MenuConfig {
 
  private:
   // Configures a MenuConfig as appropriate for the current platform.
-  void Init(const ui::NativeTheme* theme);
-
-  // TODO: temporary until we standardize.
-  void InitAura(const ui::NativeTheme* theme);
+  void Init();
 };
 
 }  // namespace views