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),

[Evan Stade, 2015/12/07 19:51:42]

I think it's fairly confusing to have this common initializer block. It's nigh
impossible to tell which parts of this actually matter to which platforms. Can
we move this to each platform file and only set the defaults that actually
matter (i.e. aren't overridden in init)?

You/someone could also do this as a follow-up if you don't want to make it part
of this CL.

[tapted, 2015/12/08 11:49:23]

I think a follow-up is best - since it will need a bit of scrutiny to ensure the
values are moved over correctly.

There might be some nicer things to try too, like `bzero`ing the struct in the
constructor, or using a static initializer once the FontList is moved out.

       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