Autofill: Use field maxlength to improve credit card date matching.

components/autofill/core/browser/credit_card_field.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_field.h"
 
 #include <stddef.h>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/stl_util.h"
@@ skipping 344 matching lines @@
                           base::ASCIIToUTF16("^(yy|yyyy)$"),
                           kMatchTelAndSelect,
                           &expiration_year_)) {
     return true;
   }
 
   // If that fails, try to parse a combined expiration field.
   // Look for a 2-digit year first.
   // We allow <select> fields, because they're used e.g. on qvc.com.
   scanner->RewindTo(month_year_saved_cursor);
+
+  static int kMinimum2YearCcExpLength = strlen("12/14");
+  int current_field_max_length = scanner->Cursor()->max_length;
+  if (current_field_max_length > 0 &&
+      current_field_max_length < kMinimum2YearCcExpLength) {
+    return false;
+  }
+
   if (ParseFieldSpecifics(scanner,
                           base::UTF8ToUTF16(kExpirationDate2DigitYearRe),
                           kMatchTelAndSelect,
                           &expiration_date_)) {
     exp_year_type_ = CREDIT_CARD_EXP_DATE_2_DIGIT_YEAR;
     expiration_month_ = nullptr;
     return true;
   }
 
   if (ParseFieldSpecifics(scanner,
                           base::UTF8ToUTF16(kExpirationDateRe),
                           kMatchTelAndSelect,
                           &expiration_date_)) {
+    static int kMinimum4YearCcExpLength = strlen("12/2014");
+    if (current_field_max_length > 0 &&
+        current_field_max_length < kMinimum4YearCcExpLength) {
+      exp_year_type_ = CREDIT_CARD_EXP_DATE_2_DIGIT_YEAR;
+    }
     expiration_month_ = nullptr;
     return true;
   }
 
   return false;
 }
 
 ServerFieldType CreditCardField::GetExpirationYearType() const {
   return (expiration_date_
               ? exp_year_type_
               : ((expiration_year_ && expiration_year_->max_length == 2)
                      ? CREDIT_CARD_EXP_2_DIGIT_YEAR
                      : CREDIT_CARD_EXP_4_DIGIT_YEAR));
 }
 
 }  // namespace autofill