mash: Convert WebNotificationTray to wm common types

ash/system/web_notification/ash_popup_alignment_delegate.h

Index: ash/system/web_notification/ash_popup_alignment_delegate.h
diff --git a/ash/system/web_notification/ash_popup_alignment_delegate.h b/ash/system/web_notification/ash_popup_alignment_delegate.h
index 11eab271195af1592a845561ee08d807873727a5..7d1f2f49c7e6595d30efc1c741c2fd1134587ee6 100644
--- a/ash/system/web_notification/ash_popup_alignment_delegate.h
+++ b/ash/system/web_notification/ash_popup_alignment_delegate.h
@@ -55,6 +55,9 @@ class ASH_EXPORT AshPopupAlignmentDelegate
   bool IsTopDown() const override;
   bool IsFromLeft() const override;
   void RecomputeAlignment(const display::Display& display) override;
+  void ConfigureWidgetInitParamsForContainer(
+      views::Widget* widget,
+      views::Widget::InitParams* init_params) override;
 
  private:
   friend class AshPopupAlignmentDelegateTest;