[WebPayments] Setting hidden views in view stack invisible

chrome/browser/ui/views/payments/view_stack.h

Index: chrome/browser/ui/views/payments/view_stack.h
diff --git a/chrome/browser/ui/views/payments/view_stack.h b/chrome/browser/ui/views/payments/view_stack.h
index 9d834e0ef531f58d6de4b15261414b00bde6b254..0472c6c9fc7f96c266767cede1f7ea8df36f028a 100644
--- a/chrome/browser/ui/views/payments/view_stack.h
+++ b/chrome/browser/ui/views/payments/view_stack.h
@@ -61,6 +61,9 @@ class ViewStack : public views::BoundsAnimatorObserver,
   // Returns the top state of the stack, used in tests.
   views::View* top() { return stack_.back().get(); }
 
+  // Marks all views, except the topmost, as invisible.
+  void HideCoveredViews();
+
   void UpdateAnimatorBounds(
       views::BoundsAnimator* animator, const gfx::Rect& target);