[WebPayments] Factor out sheet-specific logic in Controllers.

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

+// Copyright 2016 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_PAYMENT_SHEET_VIEW_CONTROLLER_H_
+#define CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_SHEET_VIEW_CONTROLLER_H_
+
+#include "chrome/browser/ui/views/payments/payment_request_sheet_controller.h"
+
+#include "ui/views/controls/button/button.h"
+
+namespace views {
+class View;
+}
+
+namespace payments {
+
+// The PaymentRequestSheetController subtype for the Payment Sheet screen of the
+// Payment Request dialog.
+class PaymentSheetViewController : public PaymentRequestSheetController,
+                                   public views::ButtonListener {
+ public:
+  PaymentSheetViewController(PaymentRequestImpl* impl,
+                             PaymentRequestDialog* dialog);
+  ~PaymentSheetViewController() override {}
+
+  static std::unique_ptr<views::View> CreateView(
+      PaymentSheetViewController* controller);
+
+ private:
+  // views::ButtonListener:
+  void ButtonPressed(views::Button* sender, const ui::Event& event) override;
+
+  DISALLOW_COPY_AND_ASSIGN(PaymentSheetViewController);
+};
+
+}  // namespace payments
+
+#endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_SHEET_VIEW_CONTROLLER_H_