Autofill: Set requirements for number of recognized fields in an autofillable 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 e93621012de98cda8af744caa37081fded771b8f..d132d6e28b218cbabe715bd0046f50388c727681 100644
--- a/components/autofill/core/browser/form_structure.h
+++ b/components/autofill/core/browser/form_structure.h
@@ -43,7 +43,7 @@ struct FormDataPredictions;
 // in the fields along with additional information needed by Autofill.
 class FormStructure {
  public:
-  FormStructure(const FormData& form);
+  explicit FormStructure(const FormData& form);
   virtual ~FormStructure();
 
   // Runs several heuristics against the form fields to determine their possible
@@ -187,6 +187,8 @@ class FormStructure {
   bool operator==(const FormData& form) const;
   bool operator!=(const FormData& form) const;
 
+  void set_is_unowned() { is_unowned_ = true; }
+
  private:
   friend class FormStructureTest;
   FRIEND_TEST_ALL_PREFIXES(AutofillDownloadTest, QueryAndUploadTest);
@@ -254,6 +256,9 @@ class FormStructure {
   // True if the form contains at least one password field.
   bool has_password_field_;
 
+  // True if the form is unowned, i.e. not for a <form>.
+  bool is_unowned_;
+
   DISALLOW_COPY_AND_ASSIGN(FormStructure);
 };