[Payments] Add the "Cards accepted" row at the top of CC editor.

components/payments/payment_request.h

Index: components/payments/payment_request.h
diff --git a/components/payments/payment_request.h b/components/payments/payment_request.h
index cd54b7cbcebac0e7c0f69c4430af6aa567740a0c..72e334de5df571f3098a46bdb3f2aac4791da155 100644
--- a/components/payments/payment_request.h
+++ b/components/payments/payment_request.h
@@ -39,7 +39,7 @@ class PaymentRequest : payments::mojom::PaymentRequest {
 
   // payments::mojom::PaymentRequest "stub"
   void Init(payments::mojom::PaymentRequestClientPtr client,
-            std::vector<payments::mojom::PaymentMethodDataPtr> methodData,
+            std::vector<payments::mojom::PaymentMethodDataPtr> method_data,
             payments::mojom::PaymentDetailsPtr details,
             payments::mojom::PaymentOptionsPtr options) override;
   void Show() override;
@@ -96,11 +96,18 @@ class PaymentRequest : payments::mojom::PaymentRequest {
   // card.
   autofill::CreditCard* GetCurrentlySelectedCreditCard();
 
+  // Validates the |method_data| and fills |supported_card_networks_|.
+  void PopulateValidatedMethodData(
+      const std::vector<payments::mojom::PaymentMethodDataPtr>& method_data);
+
   autofill::PersonalDataManager* personal_data_manager() {
     return delegate_->GetPersonalDataManager();
   }
 
   payments::mojom::PaymentDetails* details() { return details_.get(); }
+  const std::set<std::string>& supported_card_networks() {

[please use gerrit instead, 2017/02/16 22:16:11]

Let's use a vector, because order carries meaning to merchants. For example,
AmEx might pay to the merchant to show AmEx icon first. Chrome on Android
currently preserves the merchant's order when displaying the header in the card
editor. This order can also be used as a signal when sorting credit cards, but
we haven't done that yet, as that's lower priority, given that frecency does a
great job so far.

[Mathieu, 2017/02/17 15:06:47]

Done

+    return supported_card_networks_;
+  }
   content::WebContents* web_contents() { return web_contents_; }
 
  private:
@@ -119,6 +126,8 @@ class PaymentRequest : payments::mojom::PaymentRequest {
   payments::mojom::PaymentRequestClientPtr client_;
   payments::mojom::PaymentDetailsPtr details_;
   std::unique_ptr<CurrencyFormatter> currency_formatter_;
+  // A set of supported basic card networks.
+  std::set<std::string> supported_card_networks_;
 
   // Profiles may change due to (e.g.) sync events, so profiles are cached after
   // loading and owned here. They are populated once only, and ordered by