[Autofill] Fill fields that have an autocomplete attributes even if not in a form.

components/autofill/core/browser/form_structure.h

Index: components/autofill/core/browser/form_structure.h
diff --git a/components/autofill/core/browser/form_structure.h b/components/autofill/core/browser/form_structure.h
index 1a14f8d76bd7cdbb1b8aeb199b451a786e62e16b..f789f5c44334fb2d27e35b74c3c6bccbe2393c01 100644
--- a/components/autofill/core/browser/form_structure.h
+++ b/components/autofill/core/browser/form_structure.h
@@ -301,6 +301,9 @@ class FormStructure {
   // True if the form is a <form>.
   bool is_form_tag_;
 
+  // True if the form is made of unowned fields in a non checkout flow.
+  bool is_formless_checkout_;
+
   DISALLOW_COPY_AND_ASSIGN(FormStructure);
 };