[Autofill] Autofill fails to fill credit card number when split across fields.

components/autofill/core/browser/credit_card_field.cc

Index: components/autofill/core/browser/credit_card_field.cc
diff --git a/components/autofill/core/browser/credit_card_field.cc b/components/autofill/core/browser/credit_card_field.cc
index 73dc90db9fc32658b470ec80b5d732fc5865e73d..f82dc063293ba3741b28ca440c6c907e4be366ad 100644
--- a/components/autofill/core/browser/credit_card_field.cc
+++ b/components/autofill/core/browser/credit_card_field.cc
@@ -19,6 +19,10 @@
 
 namespace autofill {
 
+// Credit card numbers are at most 19 digits in length.
+// [Ref: http://en.wikipedia.org/wiki/Bank_card_number]
+static const size_t kMaxValidCardNumberSize = 19;
+
 // static
 FormField* CreditCardField::Parse(AutofillScanner* scanner) {
   if (scanner->IsEnd())
@@ -26,6 +30,7 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
 
   scoped_ptr<CreditCardField> credit_card_field(new CreditCardField);
   size_t saved_cursor = scanner->SaveCursor();
+  bool form_has_valid_card_number_fields = true;
 
   // Credit card fields can appear in many different orders.
   // We loop until no more credit card related fields are found, see |break| at
@@ -58,7 +63,7 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
       // for the cardholder's first and last name if they have the labels "cfnm"
       // and "clnm".
       scanner->SaveCursor();
-      const AutofillField* first;
+      AutofillField* first;
       if (ParseField(scanner, base::ASCIIToUTF16("^cfnm"), &first) &&
           ParseField(scanner,
                      base::ASCIIToUTF16("^clnm"),
@@ -91,8 +96,32 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
     }
 
     pattern = base::UTF8ToUTF16(autofill::kCardNumberRe);
-    if (!credit_card_field->number_ &&
-        ParseField(scanner, pattern, &credit_card_field->number_)) {
+    AutofillField* current_number_field;
+    if (ParseField(scanner, pattern, &current_number_field)) {
+      // Avoid autofilling any credit card number field having very low or high
+      // |start_index| on the HTML form.
+      size_t start_index = 0;
+      if (!credit_card_field->numbers_.empty()) {
+        size_t last_number_field_size =
+            credit_card_field->numbers_.back()->credit_card_number_offset() +
+            credit_card_field->numbers_.back()->max_length;
+
+        // In some cases, HTML form may have credit card number split across
+        // multiple input fields and either one or cumulatively having
+        // |max_length| more than |kMaxValidCardNumberSize|, mark these input
+        // form fields as invalid and skip autofilling them.
+        if (last_number_field_size == 0U ||
+            last_number_field_size >= kMaxValidCardNumberSize) {
+          // Mark that the credit card number splits are invalid. But keep
+          // scanning HTML form so that cursor moves beyond related fields.
+          form_has_valid_card_number_fields = false;
+        }
+
+        start_index = last_number_field_size;
+      }
+
+      current_number_field->set_credit_card_number_offset(start_index);
+      credit_card_field->numbers_.push_back(current_number_field);
       continue;
     }
 
@@ -162,6 +191,11 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
     break;
   }
 
+  // Cases where heuristic misinterprets input field as credit card number
+  // field, refuse to autofill credit card number fields.
+  if (!form_has_valid_card_number_fields)
+    credit_card_field->numbers_.clear();
+
   // Some pages have a billing address field after the cardholder name field.
   // For that case, allow only just the cardholder name field.  The remaining
   // CC fields will be picked up in a following CreditCardField.
@@ -175,7 +209,9 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
   // a strong enough signal that this is a credit card.  It is possible that
   // the number and name were parsed in a separate part of the form.  So if
   // the cvc and date were found independently they are returned.
-  if ((credit_card_field->number_ || credit_card_field->verification_) &&
+  if ((!credit_card_field->numbers_.empty() ||
+       credit_card_field->verification_ ||
+       !form_has_valid_card_number_fields) &&
       (credit_card_field->expiration_date_ ||
        (credit_card_field->expiration_month_ &&
         credit_card_field->expiration_year_))) {
@@ -190,7 +226,6 @@ CreditCardField::CreditCardField()
     : cardholder_(NULL),
       cardholder_last_(NULL),
       type_(NULL),
-      number_(NULL),
       verification_(NULL),
       expiration_month_(NULL),
       expiration_year_(NULL),
@@ -198,8 +233,15 @@ CreditCardField::CreditCardField()
       exp_year_type_(CREDIT_CARD_EXP_DATE_4_DIGIT_YEAR) {
 }
 
+CreditCardField::~CreditCardField() {
+}
+
 bool CreditCardField::ClassifyField(ServerFieldTypeMap* map) const {
-  bool ok = AddClassification(number_, CREDIT_CARD_NUMBER, map);
+  bool ok = true;
+  for (size_t index = 0; index < numbers_.size(); ++index) {
+    ok = ok && AddClassification(numbers_[index], CREDIT_CARD_NUMBER, map);
+  }
+
   ok = ok && AddClassification(type_, CREDIT_CARD_TYPE, map);
   ok = ok &&
        AddClassification(verification_, CREDIT_CARD_VERIFICATION_CODE, map);