make menus, bubbles, etc. top level windows on aura

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index 65c65da0b5d37f46ff2a21dfdb8ad5da35d7161e..04b474c9b1465206294c2906211902a1684c93e7 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -346,6 +346,10 @@ void Widget::Init(const InitParams& in_params) {
        params.type != InitParams::TYPE_CONTROL &&
        params.type != InitParams::TYPE_TOOLTIP);
   params.top_level = is_top_level_;
+#if defined(OS_WIN) && defined(USE_AURA)
+  // It'll need to be faded in if it's top level and not the main window.
+  params.transparent = is_top_level_ && params.type != InitParams::TYPE_WINDOW;
+#endif
 
   if (ViewsDelegate::views_delegate)
     ViewsDelegate::views_delegate->OnBeforeWidgetInit(&params, this);