Linux Aura: Fix overlay shadows on notifications

ui/message_center/views/toast_contents_view.cc

Index: ui/message_center/views/toast_contents_view.cc
diff --git a/ui/message_center/views/toast_contents_view.cc b/ui/message_center/views/toast_contents_view.cc
index ece02045e2fdcb49234ac0a46543c31cbeffa028..287ceb32c9a6aa13c69f7aec1b82f51013cb442d 100644
--- a/ui/message_center/views/toast_contents_view.cc
+++ b/ui/message_center/views/toast_contents_view.cc
@@ -365,7 +365,7 @@ void ToastContentsView::CreateWidget(
     PopupAlignmentDelegate* alignment_delegate) {
   views::Widget::InitParams params(views::Widget::InitParams::TYPE_POPUP);
   params.keep_on_top = true;
-  params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
+  params.opacity = views::Widget::InitParams::INFER_OPACITY;
   params.delegate = this;
   views::Widget* widget = new views::Widget();
   alignment_delegate->ConfigureWidgetInitParamsForContainer(widget, &params);