[Autofill] Don't validate China UnionPay cards with the Luhn checksum.

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 "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 60 matching lines @@
   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)
     return false;
+  if (type == kUnionPay && (number.size() < 16 || number.size() > 19))
+    return false;
   if (type == kVisaCard && number.size() != 13 && number.size() != 16)
     return false;
   if (type == kGenericCard && (number.size() < 12 || number.size() > 19))
     return false;
 
+  // Unlike all the other supported types, UnionPay cards lack Luhn checksum
+  // validation.
+  if (type == kUnionPay)
+    return true;
+
   // Use the Luhn formula [3] to validate the number.
   // [3] http://en.wikipedia.org/wiki/Luhn_algorithm
   int sum = 0;
   bool odd = false;
   for (base::string16::reverse_iterator iter = number.rbegin();
        iter != number.rend();
        ++iter) {
     if (!IsAsciiDigit(*iter))
       return false;
 
@@ skipping 108 matching lines @@
                                        number_string.begin() + 9),
                          &serial)
       || serial == 0) {
     return false;
   }
 
   return true;
 }
 
 }  // namespace autofill