MacViews: Implement Full Keyboard Access.

ui/views/controls/menu/menu_controller_unittest.cc

Index: ui/views/controls/menu/menu_controller_unittest.cc
diff --git a/ui/views/controls/menu/menu_controller_unittest.cc b/ui/views/controls/menu/menu_controller_unittest.cc
index 5967eae5f83075b367d9bddc542fabcae18e6c56..2dd80af066eba30fde582bf532b85df275900552 100644
--- a/ui/views/controls/menu/menu_controller_unittest.cc
+++ b/ui/views/controls/menu/menu_controller_unittest.cc
@@ -443,6 +443,7 @@ class MenuControllerTest : public ViewsTestBase {
     for (int i = 0; i < 3; ++i) {
       LabelButton* button =
           new LabelButton(nullptr, base::ASCIIToUTF16("Label"));
+      // This is an in-menu button. Hence it must be always focusable.
       button->SetFocusBehavior(View::FocusBehavior::ALWAYS);
       item_view->AddChildView(button);
     }