mash: Remove WmWindow usage from ash/system/web_notification

ui/views/bubble/tray_bubble_view.h

Index: ui/views/bubble/tray_bubble_view.h
diff --git a/ui/views/bubble/tray_bubble_view.h b/ui/views/bubble/tray_bubble_view.h
index 93fde7af259485bcfbc7cf366af2b5ffd7efdfa0..7aa054d0713e2ae462012233ac8c18230c4627ff 100644
--- a/ui/views/bubble/tray_bubble_view.h
+++ b/ui/views/bubble/tray_bubble_view.h
@@ -63,6 +63,9 @@ class VIEWS_EXPORT TrayBubbleView : public BubbleDialogDelegateView,
 
     // Called before Widget::Init() on |bubble_widget|. Allows |params| to be
     // modified.
+    // TODO(jamescook): Eliminate this method. It was introduced to let mash set
+    // the widget container back when mash could not use aura::Window. Now the
+    // anchor view should be sufficient.
     virtual void OnBeforeBubbleWidgetInit(Widget* anchor_widget,
                                           Widget* bubble_widget,
                                           Widget::InitParams* params) const = 0;