[Payments] Fix bug in shipping option selection.

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

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_PAYMENTS_SHIPPING_OPTION_VIEW_CONTROLLER_H_
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_SHIPPING_OPTION_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"
+#include "components/payments/content/payment_request_spec.h"
 
 namespace payments {
 
-class PaymentRequestSpec;
 class PaymentRequestState;
 
-class ShippingOptionViewController : public PaymentRequestSheetController {
+class ShippingOptionViewController : public PaymentRequestSheetController,
+                                     public PaymentRequestSpec::Observer {
  public:
   ShippingOptionViewController(PaymentRequestSpec* spec,
                                PaymentRequestState* state,
                                PaymentRequestDialogView* dialog);
   ~ShippingOptionViewController() override;
 
+  // PaymentRequestSpec::Observer:
+  void OnInvalidSpecProvided() override {}
+  void OnSpecUpdated() override;
+
  private:
   // PaymentRequestSheetController:
   base::string16 GetSheetTitle() override;
   void FillContentView(views::View* content_view) override;
   std::unique_ptr<views::View> CreateExtraFooterView() override;
 
   PaymentRequestItemList shipping_option_list_;
 
   DISALLOW_COPY_AND_ASSIGN(ShippingOptionViewController);
 };
 
 }  // namespace payments
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_SHIPPING_OPTION_VIEW_CONTROLLER_H_