Fix menu corners: the menu background was being painted as a rect when in fact,

ui/views/controls/menu/menu_host.cc

Index: ui/views/controls/menu/menu_host.cc
diff --git a/ui/views/controls/menu/menu_host.cc b/ui/views/controls/menu/menu_host.cc
index bea46ac169922e5271b83a90b6788360a65e1370..af972c49d80b5813213b9646283735445e78a837 100644
--- a/ui/views/controls/menu/menu_host.cc
+++ b/ui/views/controls/menu/menu_host.cc
@@ -36,6 +36,7 @@ void MenuHost::InitMenuHost(Widget* parent,
   params.has_dropshadow = true;
   params.parent = parent ? parent->GetNativeView() : NULL;
   params.bounds = bounds;
+  params.transparent = true;
   Init(params);
 
   if (ui::NativeTheme::IsNewMenuStyleEnabled()) {
@@ -46,6 +47,7 @@ void MenuHost::InitMenuHost(Widget* parent,
   }
 
   SetContentsView(contents_view);
+  SetOpacity(0);
   ShowMenuHost(do_capture);
 }