[Web Payments] Refactor the row display code.

chrome/browser/ui/views/payments/payment_request_row_view.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_PAYMENT_REQUEST_ROW_VIEW_H_
+#define CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_ROW_VIEW_H_
+
+#include "base/macros.h"
+#include "ui/views/controls/button/custom_button.h"
+
+namespace payments {
+
+// This class implements a clickable row of the Payment Request dialog that
+// darkens on hover and displays a horizontal ruler on its lower bound.
+class PaymentRequestRowView : public views::CustomButton {
+ public:
+  explicit PaymentRequestRowView(views::ButtonListener* listener);
+
+  // views::CustomButton:
+  void StateChanged() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PaymentRequestRowView);
+};
+
+}  // namespace payments
+
+#endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_ROW_VIEW_H_