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

components/autofill/core/browser/validation.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/autofill/core/browser/validation.h"
 
 #include <stddef.h>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
@@ skipping 25 matching lines @@
 }
 
 bool IsValidCreditCardNumber(const base::string16& text) {
   base::string16 number = CreditCard::StripSeparators(text);
 
   // Credit card numbers are at most 19 digits in length [1]. 12 digits seems to
   // be a fairly safe lower-bound [2].  Specific card issuers have more rigidly
   // 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;
   if (type == kDinersCard && number.size() != 14)
     return false;
   if (type == kDiscoverCard && number.size() != 16)
     return false;
   if (type == kJCBCard && number.size() != 16)
     return false;
   if (type == kMasterCard && number.size() != 16)
@@ skipping 125 matching lines @@
                                              number_string.begin() + 9),
                          &serial)
       || serial == 0) {
     return false;
   }
 
   return true;
 }
 
 }  // namespace autofill