Autofill: Better recognize credit card fields.

components/autofill/core/browser/credit_card_field.h

Index: components/autofill/core/browser/credit_card_field.h
diff --git a/components/autofill/core/browser/credit_card_field.h b/components/autofill/core/browser/credit_card_field.h
index 4647f2fc05847aed99e6547eab4a1a52c5e27c5d..7d0ee17b09f484b821b7b1a4f0b66d21b631f3f3 100644
--- a/components/autofill/core/browser/credit_card_field.h
+++ b/components/autofill/core/browser/credit_card_field.h
@@ -31,6 +31,19 @@ class CreditCardField : public FormField {
  private:
   friend class CreditCardFieldTest;
 
+  // Examines the current field pointed to by |scanner|, if it exists, and
+  // returns true if the field has a high chance of being of a given type.
+  static bool LikelyCardNumberField(AutofillScanner* scanner);
+  static bool LikelyCardType(AutofillScanner* scanner);
+
+  // Same as above, but a bit less likely since what looks like a CVC field may
+  // also be part of a credit card field.
+  static bool MayBeCardCVCField(AutofillScanner* scanner);
+
+  // A couple common arguments used for match types.
+  static const int kMatchNumAndTel;
+  static const int kMatchNumTelAndPass;
+
   CreditCardField();
 
   // Parses the expiration month/year/date fields. Returns true if it finds