[Payments] Desktop: implement shipping address/option change

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

Index: chrome/browser/ui/views/payments/payment_sheet_view_controller.h
diff --git a/chrome/browser/ui/views/payments/payment_sheet_view_controller.h b/chrome/browser/ui/views/payments/payment_sheet_view_controller.h
index e3d55ab8c9086aa54453f43b64519f08bde40535..430b04ca10f79fe0037b848a630b597d22b80029 100644
--- a/chrome/browser/ui/views/payments/payment_sheet_view_controller.h
+++ b/chrome/browser/ui/views/payments/payment_sheet_view_controller.h
@@ -9,17 +9,17 @@
 
 #include "base/macros.h"
 #include "chrome/browser/ui/views/payments/payment_request_sheet_controller.h"
+#include "components/payments/content/payment_request_spec.h"
 #include "components/payments/content/payment_request_state.h"
 
 namespace payments {
 
-class PaymentRequestSpec;
-class PaymentRequestState;
 class PaymentRequestDialogView;
 
 // The PaymentRequestSheetController subtype for the Payment Sheet screen of the
 // Payment Request dialog.
 class PaymentSheetViewController : public PaymentRequestSheetController,
+                                   public PaymentRequestSpec::Observer,
                                    public PaymentRequestState::Observer {
  public:
   // Does not take ownership of the arguments, which should outlive this object.
@@ -28,6 +28,10 @@ class PaymentSheetViewController : public PaymentRequestSheetController,
                              PaymentRequestDialogView* dialog);
   ~PaymentSheetViewController() override;
 
+  // PaymentRequestSpec::Observer:
+  void OnInvalidSpecProvided() override {}
+  void OnSpecUpdated() override;
+
   // PaymentRequestState::Observer:
   void OnSelectedInformationChanged() override;