Don't ever attempt to upload credit cards whose numbers match.

components/autofill/core/browser/credit_card.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/credit_card.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 580 matching lines @@
   if ((!name_on_card_.empty() && name_on_card_ != other.name_on_card_) ||
       (expiration_month_ != 0 &&
        expiration_month_ != other.expiration_month_) ||
       (expiration_year_ != 0 && expiration_year_ != other.expiration_year_)) {
     return false;
   }
 
   if (number_.empty())
     return true;
 
-  if (other.record_type() == FULL_SERVER_CARD)
-    return StripSeparators(number_) == StripSeparators(other.number_);
+  return HasSameNumberAs(other);
+}
 
+bool CreditCard::HasSameNumberAs(const CreditCard& other) const {
   // For masked cards, this is the best we can do to compare card numbers.
-  return TypeAndLastFourDigits() == other.TypeAndLastFourDigits();
+  if (record_type() == MASKED_SERVER_CARD ||
+      other.record_type() == MASKED_SERVER_CARD) {
+    return TypeAndLastFourDigits() == other.TypeAndLastFourDigits();
+  }
+
+  return StripSeparators(number_) == StripSeparators(other.number_);
 }
 
 bool CreditCard::operator==(const CreditCard& credit_card) const {
   return guid() == credit_card.guid() &&
          origin() == credit_card.origin() &&
          Compare(credit_card) == 0;
 }
 
 bool CreditCard::operator!=(const CreditCard& credit_card) const {
   return !operator==(credit_card);
@@ skipping 172 matching lines @@
 const char kAmericanExpressCard[] = "americanExpressCC";
 const char kDinersCard[] = "dinersCC";
 const char kDiscoverCard[] = "discoverCC";
 const char kGenericCard[] = "genericCC";
 const char kJCBCard[] = "jcbCC";
 const char kMasterCard[] = "masterCardCC";
 const char kUnionPay[] = "unionPayCC";
 const char kVisaCard[] = "visaCC";
 
 }  // namespace autofill