[Autofill Assistant] Add new credit card field

This change adds the non-padded month for credit card expiry to deal
with forms where the month is "1" for January (instead of "01").

Bug: b/168227057
Change-Id: Ibf030936e638ea5df57fe8e3da36fe6cf06589ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2461314
Commit-Queue: Sandro Maggi <sandromaggi@google.com>
Reviewed-by: Clemens Arbesser <arbesser@google.com>
Cr-Commit-Position: refs/heads/master@{#815568}

components/autofill_assistant/browser/field_formatter.cc

@@ -133,6 +133,14 @@ std::map<std::string, std::string> CreateAutofillMappings<autofill::CreditCard>(
         AutofillFormatProto::CREDIT_CARD_NUMBER_LAST_FOUR_DIGITS))] =
         last_four_digits;
   }
+  int month;
+  if (base::StringToInt(
+          credit_card.GetInfo(autofill::CREDIT_CARD_EXP_MONTH, locale),
+          &month)) {
+    mappings[base::NumberToString(static_cast<int>(
+        AutofillFormatProto::CREDIT_CARD_NON_PADDED_EXP_MONTH))] =
+        base::NumberToString(month);
+  }
 
   return mappings;
 }

components/autofill_assistant/browser/field_formatter_unittest.cc

@@ -108,6 +108,11 @@ TEST(FieldFormatterTest, CreditCard) {
   EXPECT_EQ(*FormatString("${-2} ${-5}",
                           CreateAutofillMappings(credit_card, "en-US")),
             "visa Visa");
+
+  // CREDIT_CARD_NON_PADDED_EXP_MONTH
+  EXPECT_EQ(
+      *FormatString("${-7}", CreateAutofillMappings(credit_card, "en-US")),
+      "1");
 }
 
 TEST(FieldFormatterTest, SpecialCases) {
@@ -189,6 +194,7 @@ TEST(FieldFormatterTest, AddsAllProfileFields) {
 
 TEST(FieldFormatterTest, AddsAllCreditCardFields) {
   std::map<std::string, std::string> expected_values = {
+      {"-7", "8"},
       {"-5", "Visa"},
       {"-4", "1111"},
       {"-2", "visa"},

components/autofill_assistant/browser/generic_ui.proto

@@ -199,6 +199,7 @@ message AutofillFormatProto {
     CREDIT_CARD_NETWORK_FOR_DISPLAY = -5;
     // Currently only US states are supported. The state name is in lower case.
     ADDRESS_HOME_STATE_NAME = -6;
+    CREDIT_CARD_NON_PADDED_EXP_MONTH = -7;
   }
   // The format string to use. May contain one or multiple "${key}"
   // placeholders, where the key is an integer corresponding to

components/autofill_assistant/browser/service.proto

@@ -431,6 +431,7 @@ enum KeyboardValueFillStrategy {
   SIMULATE_KEY_PRESSES_SELECT_VALUE = 3;
 }
 
+// Note: On multiple matches, the first one will be selected.
 enum DropdownSelectStrategy {
   UNSPECIFIED_SELECT_STRATEGY = 0;