[Autofill] Credit Card Autofill Last Used Date Experiment

components/autofill/core/browser/credit_card.cc

Index: components/autofill/core/browser/credit_card.cc
diff --git a/components/autofill/core/browser/credit_card.cc b/components/autofill/core/browser/credit_card.cc
index 3b402eae9e873dbb85ae52383d1ebaa1a1e4d2bd..a49e75b3e98776494b5932b992f65aa1407ee1cc 100644
--- a/components/autofill/core/browser/credit_card.cc
+++ b/components/autofill/core/browser/credit_card.cc
@@ -783,6 +783,37 @@ void CreditCard::SetNumber(const base::string16& number) {
     type_ = GetCreditCardType(StripSeparators(number_));
 }
 
+base::string16 CreditCard::LastUsedDateAsString() const {
+  base::Time::Exploded exploded;
+  use_date().LocalExplode(&exploded);
+  base::string16 month = FormatDateTo2Digit(exploded.month);
+  base::string16 day_of_month = FormatDateTo2Digit(exploded.day_of_month);
+  base::string16 hour = FormatDateTo2Digit(exploded.hour);
+  base::string16 minute = FormatDateTo2Digit(exploded.minute);

[csashi, 2017/01/03 20:54:06]

You do not need hour and minutes unless use_count() > 1.

[jiahuiguo, 2017/01/18 00:13:44]

Good point!

+  return use_count() > 1
+             ? l10n_util::GetStringFUTF16(
+                 IDS_AUTOFILL_CREDIT_CARD_LAST_USED_DATE_LABEL,
+                 month,
+                 day_of_month,
+                 hour,
+                 minute)
+             : l10n_util::GetStringFUTF16(
+                 IDS_AUTOFILL_CREDIT_CARD_ADDED_TO_CHROME_DATE_LABEL,
+                 month,
+                 day_of_month);
+}
+
+base::string16 CreditCard::FormatDateTo2Digit(int date_info) const {
+  DCHECK(date_info > 0);
+  base::string16 dateIn2Digit = base::IntToString16(date_info);
+  if (date_info >= 10)
+    return dateIn2Digit;
+
+  base::string16 zero = ASCIIToUTF16("0");
+  zero.append(dateIn2Digit);
+  return zero;

[csashi, 2017/01/03 20:54:06]

You are not returning zero. May be call this padded_date (or equivalent)?

[jiahuiguo, 2017/01/18 00:13:44]

Done.

+}
+
 void CreditCard::RecordAndLogUse() {
   UMA_HISTOGRAM_COUNTS_1000("Autofill.DaysSinceLastUse.CreditCard",
                             (base::Time::Now() - use_date()).InDays());