Add billing address as a mandatory field of Payments credit cards.

components/autofill/core/browser/validation.cc

Index: components/autofill/core/browser/validation.cc
diff --git a/components/autofill/core/browser/validation.cc b/components/autofill/core/browser/validation.cc
index cbab098922462f26923b3cfa2230f9f614014696..9fb969f3a285f8cd7cbd21d9c854b4aad26973fc 100644
--- a/components/autofill/core/browser/validation.cc
+++ b/components/autofill/core/browser/validation.cc
@@ -141,6 +141,10 @@ CreditCardCompletionStatus GetCompletionStatusForCard(
     status |= CREDIT_CARD_NO_CARDHOLDER;
   }
 
+  if (card.billing_address_id().empty()) {

[sebsg, 2017/05/02 22:58:55]

This would be a bit more involved but we might want to check that the billing
address id is associated with a profile that we have on file. We can add it
later if you want (but let's create a bug in that case).

[MAD, 2017/05/03 16:15:19]

Done.

+    status |= CREDIT_CARD_NO_BILLING_ADDRESS;
+  }
+
   return status;
 }
 
@@ -156,6 +160,9 @@ base::string16 GetCompletionMessageForCard(CreditCardCompletionStatus status) {
     case CREDIT_CARD_NO_NUMBER:
       return l10n_util::GetStringUTF16(
           IDS_PAYMENTS_CARD_NUMBER_INVALID_VALIDATION_MESSAGE);
+    case CREDIT_CARD_NO_BILLING_ADDRESS:
+      return l10n_util::GetStringUTF16(
+          IDS_PAYMENTS_CARD_BILLING_ADDRESS_REQUIRED);
     default:
       // Multiple things are missing
       return l10n_util::GetStringUTF16(IDS_PAYMENTS_MORE_INFORMATION_REQUIRED);