Change Views menus to consistently use GetNativeTheme for theming.

ui/views/controls/menu/menu_runner_impl.cc

Index: ui/views/controls/menu/menu_runner_impl.cc
diff --git a/ui/views/controls/menu/menu_runner_impl.cc b/ui/views/controls/menu/menu_runner_impl.cc
index 8ce4f3f320610f2d56af5789f52bf08057de3dc1..b8270c2beaa795d8421eade989fa7f9d4515443d 100644
--- a/ui/views/controls/menu/menu_runner_impl.cc
+++ b/ui/views/controls/menu/menu_runner_impl.cc
@@ -109,9 +109,7 @@ MenuRunner::RunResult MenuRunnerImpl::RunMenuAt(Widget* parent,
   owns_controller_ = false;
   if (!controller) {
     // No menus are showing, show one.
-    ui::NativeTheme* theme =
-        parent ? parent->GetNativeTheme() : ui::NativeTheme::instance();
-    controller = new MenuController(theme, !for_drop_, this);
+    controller = new MenuController(!for_drop_, this);
     owns_controller_ = true;
   }
   controller->set_is_combobox((run_types & MenuRunner::COMBOBOX) != 0);