Use a single views::MenuConfig instance for each platform

ui/views/controls/menu/menu_config.cc

Index: ui/views/controls/menu/menu_config.cc
diff --git a/ui/views/controls/menu/menu_config.cc b/ui/views/controls/menu/menu_config.cc
index 0d726c54002850a39de29abc159f74116f0b5bae..52c39e4d49c2cee5c0a9ea370dd874e3dbc24e6a 100644
--- a/ui/views/controls/menu/menu_config.cc
+++ b/ui/views/controls/menu/menu_config.cc
@@ -4,11 +4,11 @@
 
 #include "ui/views/controls/menu/menu_config.h"
 
-#include "build/build_config.h"
+#include "base/macros.h"
 
 namespace views {
 
-MenuConfig::MenuConfig(const ui::NativeTheme* theme)
+MenuConfig::MenuConfig()
     : arrow_color(SK_ColorBLACK),
       menu_vertical_border_size(3),
       menu_horizontal_border_size(0),
@@ -42,9 +42,15 @@ MenuConfig::MenuConfig(const ui::NativeTheme* theme)
       check_selected_combobox_item(false),
       show_delay(400),
       corner_radius(0) {
-  Init(theme);
+  Init();
 }
 
 MenuConfig::~MenuConfig() {}
 
+// static
+const MenuConfig& MenuConfig::instance() {
+  CR_DEFINE_STATIC_LOCAL(MenuConfig, instance, ());
+  return instance;
+}
+
 }  // namespace views