Change name of NativeTheme::instance() to make it clear it's web only.

ui/views/controls/menu/menu_config_aura.cc

Index: ui/views/controls/menu/menu_config_aura.cc
diff --git a/ui/views/controls/menu/menu_config_aura.cc b/ui/views/controls/menu/menu_config_aura.cc
index 659b304782e597e013ab69093d01a48f89ad5897..e2719fe16d13bfcf261c65cf177990e23d8c4d2f 100644
--- a/ui/views/controls/menu/menu_config_aura.cc
+++ b/ui/views/controls/menu/menu_config_aura.cc
@@ -57,8 +57,8 @@ void MenuConfig::InitAura(const ui::NativeTheme* theme) {
 const MenuConfig& MenuConfig::instance(const ui::NativeTheme* theme) {
   static MenuConfig* views_instance = NULL;
   if (!views_instance)
-    views_instance = new MenuConfig(theme ?
-        theme : ui::NativeTheme::instance());
+    views_instance =
+        new MenuConfig(theme ? theme : ui::NativeThemeAura::instance());
   return *views_instance;
 }
 #endif