Autofill: Better recognize credit card type fields.

components/autofill/core/browser/autofill_field.h

Index: components/autofill/core/browser/autofill_field.h
diff --git a/components/autofill/core/browser/autofill_field.h b/components/autofill/core/browser/autofill_field.h
index 1c79bb2fd001fc090115c738fb06e06054185923..19a26c23bf2c9453dab01e7315aaf5d2028136a1 100644
--- a/components/autofill/core/browser/autofill_field.h
+++ b/components/autofill/core/browser/autofill_field.h
@@ -89,6 +89,13 @@ class AutofillField : public FormFieldData {
                                             const base::string16& number,
                                             const FormFieldData& field_data);
 
+  // Returns true if the select |field| contains an option that matches |value|.
+  // If the return value is true and |index| is non-NULL, write the index of the
+  // matching option into |index|.
+  static bool FindValueInSelectControl(const FormFieldData& field,
+                                       const base::string16& value,
+                                       size_t* index);
+
  private:
   // The unique name of this field, generated by Autofill.
   base::string16 unique_name_;