[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..542d15b2ff69db4f4b28a290c8e4cbaf42ae7981 100644
--- a/components/autofill/core/browser/credit_card.cc
+++ b/components/autofill/core/browser/credit_card.cc
@@ -12,6 +12,7 @@
 #include <string>
 
 #include "base/guid.h"
+#include "base/i18n/time_formatting.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
@@ -88,6 +89,18 @@ base::string16 TypeForFill(const std::string& type) {
   return base::string16();
 }
 
+// Padding month and day info to exactly 2 digits.
+base::string16 PadTo2Digit(int32_t date_info) {
+  DCHECK(date_info > 0);
+  base::string16 date_in_2_digits = base::IntToString16(date_info);
+  if (date_info >= 10)
+    return date_in_2_digits;
+
+  base::string16 padded_date = ASCIIToUTF16("0");
+  padded_date.append(date_in_2_digits);
+  return padded_date;

[jungshik at Google, 2017/01/23 21:43:24]

Some locales do NOT use ASCII digit. So that prepending with '0' 
does not work. 

Why don't you just use TimeFormatWithPattern(time, 'MMdd')? Well, you have to
make up a 'time' corresponding to the expiration date to pass, but it'd be a
small cost to pay for the locale-aware formatting.  

[jiahuiguo, 2017/01/26 05:46:12]

Thanks for pointing this out, for the expiration date shown on a credit card, it
is ISO standard to format as "MM/YY" or "MM-YY", where the former is prefered,
so constructing such a string would be ok for different locales?

Actually the way to padding the month is from the original code, and it was used
in several places, if it is fundamentally wrong, I can fill a bug and fix it in
a following CL.  

+}
+
 }  // namespace
 
 CreditCard::CreditCard(const std::string& guid, const std::string& origin)
@@ -677,16 +690,9 @@ void CreditCard::GetSupportedTypes(ServerFieldTypeSet* supported_types) const {
 }
 
 base::string16 CreditCard::ExpirationMonthAsString() const {
-  if (expiration_month_ == 0)
-    return base::string16();
-
-  base::string16 month = base::IntToString16(expiration_month_);
-  if (expiration_month_ >= 10)
-    return month;
-
-  base::string16 zero = ASCIIToUTF16("0");
-  zero.append(month);
-  return zero;
+  return expiration_month_ == 0
+      ? base::string16()
+      : PadTo2Digit(expiration_month_);
 }
 
 base::string16 CreditCard::TypeForFill() const {
@@ -783,6 +789,34 @@ void CreditCard::SetNumber(const base::string16& number) {
     type_ = GetCreditCardType(StripSeparators(number_));
 }
 
+base::string16 CreditCard::GetLastUsedDateForDisplay(
+    bool show_expiration_date,
+    bool show_time_detail) const {
+  DCHECK(use_count() > 0);
+  // use_count() is initialized as 1 when the card is just added.
+  if (use_count() == 1) {
+    return l10n_util::GetStringFUTF16(
+        show_expiration_date
+            ? IDS_AUTOFILL_CREDIT_CARD_ADDED_DATE_LABEL_AND_EXP
+            : IDS_AUTOFILL_CREDIT_CARD_ADDED_DATE_LABEL,
+        base::TimeFormatWithPattern(use_date(), "MMMdd"));
+  }
+  // use_count() > 1 when the card has been used in autofill.
+  if (show_time_detail) {
+    return l10n_util::GetStringFUTF16(
+        show_expiration_date
+            ? IDS_AUTOFILL_CREDIT_CARD_LAST_USED_DATE_LABEL_AND_EXP_WITH_DETAIL
+            : IDS_AUTOFILL_CREDIT_CARD_LAST_USED_DATE_LABEL_WITH_DETAIL,
+        base::TimeFormatWithPattern(use_date(), "MMMddjmm"));
+  } else {
+    return l10n_util::GetStringFUTF16(
+        show_expiration_date
+            ? IDS_AUTOFILL_CREDIT_CARD_LAST_USED_DATE_LABEL_AND_EXP_NO_DETAIL
+            : IDS_AUTOFILL_CREDIT_CARD_LAST_USED_DATE_LABEL_NO_DETAIL,
+        base::TimeFormatWithPattern(use_date(), "MMMdd"));

[jungshik at Google, 2017/01/23 21:43:24]

There are 4 combinations here and they're combined with 

[jiahuiguo, 2017/01/26 05:46:12]

Done.

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