[Autofill] Credit Card Autofill Last Used Date Experiment

components/autofill/core/browser/credit_card.h

Index: components/autofill/core/browser/credit_card.h
diff --git a/components/autofill/core/browser/credit_card.h b/components/autofill/core/browser/credit_card.h
index d0a8a6eee7ee8b3b720d6e44035359baee0be127..f11e82d6a75a1399aec6ac17a06a6a88fc0d0aee 100644
--- a/components/autofill/core/browser/credit_card.h
+++ b/components/autofill/core/browser/credit_card.h
@@ -174,6 +174,9 @@ class CreditCard : public AutofillDataModel {
   // Sets |number_| to |number| and computes the appropriate card |type_|.
   void SetNumber(const base::string16& number);
 
+  // Returns the date(MM/DD) when the credit card was last used in autofill

[Jared Saul, 2017/01/04 22:01:24]

nit: Add period at end

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

Done.

+  base::string16 LastUsedDateAsString() const;
+
   // Logs the number of days since the credit card was last used and records its
   // use.
   void RecordAndLogUse();
@@ -213,6 +216,9 @@ class CreditCard : public AutofillDataModel {
   base::string16 Expiration4DigitYearAsString() const;
   base::string16 Expiration2DigitYearAsString() const;
 
+  // Formatting month or day info to exact 2 digits

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

Is it not "month *and* day" ?

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

exactly 2 digits

[jiahuiguo, 2017/01/18 00:13:45]

Done.

[jiahuiguo, 2017/01/18 00:13:45]

Done.

+  base::string16 FormatDateTo2Digit(int dateInfo) const;

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

Is it 2 digits? MM/DD is 4 digits.

[Jared Saul, 2017/01/04 22:01:23]

Yeah but this function only takes a certain part of it at a time (day, month,
etc.)  Perhaps just rename to "FormatTo2Digits(int dateInfo)" instead?

[jiahuiguo, 2017/01/18 00:13:45]

Done.

[jiahuiguo, 2017/01/18 00:13:45]

It only formats month or day for each call, return either MM or DD.

+
   // Sets |expiration_month_| to the integer conversion of |text| and returns
   // whether the operation was successful.
   bool SetExpirationMonthFromString(const base::string16& text,