[Web Payments] Add a mechanism to build item lists in the PR dialog.

chrome/browser/ui/views/payments/payment_method_view_controller.h

Index: chrome/browser/ui/views/payments/payment_method_view_controller.h
diff --git a/chrome/browser/ui/views/payments/payment_method_view_controller.h b/chrome/browser/ui/views/payments/payment_method_view_controller.h
index 8abb21626eb3c8092b97503b10752899c7881c2c..4662d2704d1beab4e43b1acb58cb5e93b0d1cc13 100644
--- a/chrome/browser/ui/views/payments/payment_method_view_controller.h
+++ b/chrome/browser/ui/views/payments/payment_method_view_controller.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_METHOD_VIEW_CONTROLLER_H_
 
 #include "base/macros.h"
+#include "chrome/browser/ui/views/payments/payment_request_item_list.h"
 #include "chrome/browser/ui/views/payments/payment_request_sheet_controller.h"
 
 namespace payments {
@@ -27,8 +28,11 @@ class PaymentMethodViewController : public PaymentRequestSheetController {
 
  private:
   // PaymentRequestSheetController:
+  std::unique_ptr<views::View> CreateExtraView() override;
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
+  PaymentRequestItemList payment_method_list_;
+
   DISALLOW_COPY_AND_ASSIGN(PaymentMethodViewController);
 };