[Payments] Auto-advance to next field after typing in valid credit card with maximum digits

components/autofill/core/browser/validation.cc

Index: components/autofill/core/browser/validation.cc
diff --git a/components/autofill/core/browser/validation.cc b/components/autofill/core/browser/validation.cc
index 7efa38cc33e0c1adb0d6276fd6ba6e6509d08570..b784a2697937f8e9586e1292376ca73cf164481a 100644
--- a/components/autofill/core/browser/validation.cc
+++ b/components/autofill/core/browser/validation.cc
@@ -43,6 +43,7 @@ bool IsValidCreditCardNumber(const base::string16& text) {
   // defined sizes.
   // [1] http://www.merriampark.com/anatomycc.htm
   // [2] http://en.wikipedia.org/wiki/Bank_card_number
+  // CardEditor.isCardNumberLengthMaxium() needs to be kept in sync.
   const char* const type = CreditCard::GetCreditCardType(text);
   if (type == kAmericanExpressCard && number.size() != 15)
     return false;