[Payments] In shipping address editor, enable required + phone validation.

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

Index: chrome/browser/ui/views/payments/shipping_address_editor_view_controller.h
diff --git a/chrome/browser/ui/views/payments/shipping_address_editor_view_controller.h b/chrome/browser/ui/views/payments/shipping_address_editor_view_controller.h
index ba014a4edd99d9e1ae5226a8b60df2fb98956bc5..61d2ee7fce73c81c7baf4e5d0c124a5b9763509b 100644
--- a/chrome/browser/ui/views/payments/shipping_address_editor_view_controller.h
+++ b/chrome/browser/ui/views/payments/shipping_address_editor_view_controller.h
@@ -58,8 +58,8 @@ class ShippingAddressEditorViewController : public EditorViewController {
     bool ValidateValue(const base::string16& value);
 
     EditorField field_;
-    // TODO(mad): Bring back when needed.
-    // ShippingAddressEditorViewController* parent_{nullptr};
+    // Raw pointer back to the owner of this class, therefore will not be null.
+    ShippingAddressEditorViewController* controller_;
 
     DISALLOW_COPY_AND_ASSIGN(ShippingAddressValidationDelegate);
   };