[Autofill] Autofill incorrectly fills credit card expiration year in 2-digit fields.

With current implementation the on parsing the credit card field heuristics
matches to the autofill::kExpirationYearRe and apparently it's assumes that a
4-digit credit card field (i.e. ServerFieldType CREDIT_CARD_EXP_DATE_4_DIGIT_YEAR).

This patch considers *maxlength* attribute in addition to see whether the feild
is 2-digit input field or not.

BUG=406247

Review URL: https://codereview.chromium.org/493393003

Cr-Commit-Position: refs/heads/master@{#291734}

3 files changed, 81 insertions, 38 deletions

diff --git a/components/autofill/core/browser/credit_card_field.cc b/components/autofill/core/browser/credit_card_field.cc
index 09dab1e..73dc90d 100644
--- a/components/autofill/core/browser/credit_card_field.cc
+++ b/components/autofill/core/browser/credit_card_field.cc
@@ -60,7 +60,8 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
       scanner->SaveCursor();
       const AutofillField* first;
       if (ParseField(scanner, base::ASCIIToUTF16("^cfnm"), &first) &&
-          ParseField(scanner, base::ASCIIToUTF16("^clnm"),
+          ParseField(scanner,
+                     base::ASCIIToUTF16("^clnm"),
                      &credit_card_field->cardholder_last_)) {
         credit_card_field->cardholder_ = first;
         continue;
@@ -71,7 +72,8 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
     // Check for a credit card type (Visa, MasterCard, etc.) field.
     base::string16 type_pattern = base::UTF8ToUTF16(autofill::kCardTypeRe);
     if (!credit_card_field->type_ &&
-        ParseFieldSpecifics(scanner, type_pattern,
+        ParseFieldSpecifics(scanner,
+                            type_pattern,
                             MATCH_DEFAULT | MATCH_SELECT,
                             &credit_card_field->type_)) {
       continue;
@@ -102,11 +104,15 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
       scanner->SaveCursor();
       pattern = base::UTF8ToUTF16(autofill::kExpirationMonthRe);
       if (!credit_card_field->expiration_month_ &&
-          ParseFieldSpecifics(scanner, pattern, MATCH_DEFAULT | MATCH_SELECT,
+          ParseFieldSpecifics(scanner,
+                              pattern,
+                              MATCH_DEFAULT | MATCH_SELECT,
                               &credit_card_field->expiration_month_)) {
         pattern = base::UTF8ToUTF16(autofill::kExpirationYearRe);
-        if (ParseFieldSpecifics(scanner, pattern, MATCH_DEFAULT | MATCH_SELECT,
-                                 &credit_card_field->expiration_year_)) {
+        if (ParseFieldSpecifics(scanner,
+                                pattern,
+                                MATCH_DEFAULT | MATCH_SELECT,
+                                &credit_card_field->expiration_year_)) {
           continue;
         }
       }
@@ -117,19 +123,21 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
         scanner->Rewind();
         pattern = base::UTF8ToUTF16(autofill::kExpirationDate2DigitYearRe);
         // We allow <select> fields, because they're used e.g. on qvc.com.
-        if (ParseFieldSpecifics(scanner, pattern,
-                                MATCH_LABEL | MATCH_VALUE | MATCH_TEXT |
-                                    MATCH_SELECT,
-                                &credit_card_field->expiration_date_)) {
-          credit_card_field->is_two_digit_year_ = true;
+        if (ParseFieldSpecifics(
+                scanner,
+                pattern,
+                MATCH_LABEL | MATCH_VALUE | MATCH_TEXT | MATCH_SELECT,
+                &credit_card_field->expiration_date_)) {
+          credit_card_field->exp_year_type_ = CREDIT_CARD_EXP_DATE_2_DIGIT_YEAR;
           continue;
         }
 
         pattern = base::UTF8ToUTF16(autofill::kExpirationDateRe);
-        if (ParseFieldSpecifics(scanner, pattern,
-                                MATCH_LABEL | MATCH_VALUE | MATCH_TEXT |
-                                    MATCH_SELECT,
-                                &credit_card_field->expiration_date_)) {
+        if (ParseFieldSpecifics(
+                scanner,
+                pattern,
+                MATCH_LABEL | MATCH_VALUE | MATCH_TEXT | MATCH_SELECT,
+                &credit_card_field->expiration_date_)) {
           continue;
         }
       }
@@ -187,14 +195,14 @@ CreditCardField::CreditCardField()
       expiration_month_(NULL),
       expiration_year_(NULL),
       expiration_date_(NULL),
-      is_two_digit_year_(false) {
+      exp_year_type_(CREDIT_CARD_EXP_DATE_4_DIGIT_YEAR) {
 }
 
 bool CreditCardField::ClassifyField(ServerFieldTypeMap* map) const {
   bool ok = AddClassification(number_, CREDIT_CARD_NUMBER, map);
   ok = ok && AddClassification(type_, CREDIT_CARD_TYPE, map);
-  ok = ok && AddClassification(verification_, CREDIT_CARD_VERIFICATION_CODE,
-                               map);
+  ok = ok &&
+       AddClassification(verification_, CREDIT_CARD_VERIFICATION_CODE, map);
 
   // If the heuristics detected first and last name in separate fields,
   // then ignore both fields. Putting them into separate fields is probably
@@ -204,27 +212,23 @@ bool CreditCardField::ClassifyField(ServerFieldTypeMap* map) const {
     ok = ok && AddClassification(cardholder_, CREDIT_CARD_NAME, map);
 
   if (expiration_date_) {
-    if (is_two_digit_year_) {
-      ok = ok && AddClassification(expiration_date_,
-                                   CREDIT_CARD_EXP_DATE_2_DIGIT_YEAR, map);
-    } else {
-      ok = ok && AddClassification(expiration_date_,
-                                   CREDIT_CARD_EXP_DATE_4_DIGIT_YEAR, map);
-    }
+    ok =
+        ok && AddClassification(expiration_date_, GetExpirationYearType(), map);
   } else {
     ok = ok && AddClassification(expiration_month_, CREDIT_CARD_EXP_MONTH, map);
-    if (is_two_digit_year_) {
-      ok = ok && AddClassification(expiration_year_,
-                                   CREDIT_CARD_EXP_2_DIGIT_YEAR,
-                                   map);
-    } else {
-      ok = ok && AddClassification(expiration_year_,
-                                   CREDIT_CARD_EXP_4_DIGIT_YEAR,
-                                   map);
-    }
+    ok =
+        ok && AddClassification(expiration_year_, GetExpirationYearType(), map);
   }
 
   return ok;
 }
 
+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
diff --git a/components/autofill/core/browser/credit_card_field.h b/components/autofill/core/browser/credit_card_field.h
index bf45e7e..64fa4ed 100644
--- a/components/autofill/core/browser/credit_card_field.h
+++ b/components/autofill/core/browser/credit_card_field.h
@@ -31,12 +31,17 @@ class CreditCardField : public FormField {
 
   CreditCardField();
 
+  // For the combined expiration field we return |exp_year_type_|; otherwise if
+  // |expiration_year_| is having year with |max_length| of 2-digits we return
+  // |CREDIT_CARD_EXP_2_DIGIT_YEAR|; otherwise |CREDIT_CARD_EXP_4_DIGIT_YEAR|.
+  ServerFieldType GetExpirationYearType() const;
+
   const AutofillField* cardholder_;  // Optional.
 
   // Occasionally pages have separate fields for the cardholder's first and
-  // last names; for such pages cardholder_ holds the first name field and
+  // last names; for such pages |cardholder_| holds the first name field and
   // we store the last name field here.
-  // (We could store an embedded NameField object here, but we don't do so
+  // (We could store an embedded |NameField| object here, but we don't do so
   // because the text patterns for matching a cardholder name are different
   // than for ordinary names, and because cardholder names never have titles,
   // middle names or suffixes.)
@@ -55,9 +60,10 @@ class CreditCardField : public FormField {
   const AutofillField* expiration_year_;
   const AutofillField* expiration_date_;
 
-  // True if the year is detected to be a 2-digit year; otherwise, we assume
-  // a 4-digit year.
-  bool is_two_digit_year_;
+  // For combined expiration field having year as 2-digits we store here
+  // |CREDIT_CARD_EXP_DATE_2_DIGIT_YEAR|; otherwise we store
+  // |CREDIT_CARD_EXP_DATE_4_DIGIT_YEAR|.
+  ServerFieldType exp_year_type_;
 
   DISALLOW_COPY_AND_ASSIGN(CreditCardField);
 };
diff --git a/components/autofill/core/browser/credit_card_field_unittest.cc b/components/autofill/core/browser/credit_card_field_unittest.cc
index 037a302..39e222f 100644
--- a/components/autofill/core/browser/credit_card_field_unittest.cc
+++ b/components/autofill/core/browser/credit_card_field_unittest.cc
@@ -347,4 +347,37 @@ TEST_F(CreditCardFieldTest, ParseMonthControl) {
             field_type_map_[ASCIIToUTF16("date2")]);
 }
 
+// Verify that heuristics <input name="ccyear" maxlength="2"/> considers
+// *maxlength* attribute while parsing 2 Digit expiration year.
+TEST_F(CreditCardFieldTest, ParseCreditCardExpYear_2DigitMaxLength) {
+  FormFieldData field;
+  field.form_control_type = "text";
+
+  field.label = ASCIIToUTF16("Card Number");
+  field.name = ASCIIToUTF16("card_number");
+  list_.push_back(new AutofillField(field, ASCIIToUTF16("number")));
+
+  field.label = ASCIIToUTF16("Expiration Date");
+  field.name = ASCIIToUTF16("ccmonth");
+  list_.push_back(new AutofillField(field, ASCIIToUTF16("month")));
+
+  field.name = ASCIIToUTF16("ccyear");
+  field.max_length = 2;
+  list_.push_back(new AutofillField(field, ASCIIToUTF16("year")));
+
+  Parse();
+  ASSERT_NE(static_cast<CreditCardField*>(NULL), field_.get());
+  EXPECT_TRUE(ClassifyField());
+  ASSERT_TRUE(field_type_map_.find(ASCIIToUTF16("number")) !=
+              field_type_map_.end());
+  EXPECT_EQ(CREDIT_CARD_NUMBER, field_type_map_[ASCIIToUTF16("number")]);
+  ASSERT_TRUE(field_type_map_.find(ASCIIToUTF16("month")) !=
+              field_type_map_.end());
+  EXPECT_EQ(CREDIT_CARD_EXP_MONTH, field_type_map_[ASCIIToUTF16("month")]);
+  ASSERT_TRUE(field_type_map_.find(ASCIIToUTF16("year")) !=
+              field_type_map_.end());
+  EXPECT_EQ(CREDIT_CARD_EXP_2_DIGIT_YEAR,
+            field_type_map_[ASCIIToUTF16("year")]);
+}
+
 }  // namespace autofill