add HideAndClose in preference to having Close sometimes magically defer

ui/views/widget/widget.h

Index: ui/views/widget/widget.h
diff --git a/ui/views/widget/widget.h b/ui/views/widget/widget.h
index 2d6e6aaff6e37d50f6448f4137f84ffbc6821483..047e858afaed7291863381cd820ba2546a2f9f4c 100644
--- a/ui/views/widget/widget.h
+++ b/ui/views/widget/widget.h
@@ -395,6 +395,10 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
   virtual void Show();
   void Hide();
 
+  // Hides the widget, and on completion of the hide animation (if any),
+  // Close()s.
+  void HideAndClose();
+
   // Like Show(), but does not activate the window.
   void ShowInactive();