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

chrome/browser/ui/views/payments/payment_request_sheet_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_REQUEST_SHEET_CONTROLLER_H_
+#define CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_SHEET_CONTROLLER_H_
+
+#include <memory>
+
+#include "base/macros.h"
+
+namespace views {
+class View;
+}
+
+namespace payments {
+
+class PaymentRequestDialog;
+class PaymentRequestImpl;
+
+// The base class for objects responsible for the creation and event handling in
+// views shown in the PaymentRequestDialog.
+class PaymentRequestSheetController {
+ public:
+  PaymentRequestSheetController(PaymentRequestImpl* impl,
+                                PaymentRequestDialog* dialog)
+    : impl_(impl),
+      dialog_(dialog) {}
+  virtual ~PaymentRequestSheetController() {}
+
+  virtual std::unique_ptr<views::View> CreateView() = 0;

[sky, 2016/12/15 16:49:44]

Technically you don't need CreateView() defined in this class, but it does make
things clearer.

+
+  // The PaymentRequestImpl object associated with this instance of the dialog.
+  PaymentRequestImpl* impl() { return impl_; }
+  // The dialog that contains and owns this object.
+  PaymentRequestDialog* dialog() { return dialog_; }
+
+ private:
+  PaymentRequestImpl* impl_;
+  PaymentRequestDialog* dialog_;
+
+  DISALLOW_COPY_AND_ASSIGN(PaymentRequestSheetController);
+};
+
+}  // namespace payments
+
+#endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_SHEET_CONTROLLER_H_