[Web Payments] Add Cancel button to all sheets

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/logging.h"
 #include "base/macros.h"
+#include "ui/views/controls/button/vector_icon_button_delegate.h"
 
 namespace views {
+class Button;
 class View;
 }
 
 namespace payments {
 
 class PaymentRequestDialogView;
 class PaymentRequest;
 
 // The base class for objects responsible for the creation and event handling in
 // views shown in the PaymentRequestDialog.
-class PaymentRequestSheetController {
+class PaymentRequestSheetController : public views::VectorIconButtonDelegate {
  public:
   // Objects of this class are owned by |dialog|, so it's a non-owned pointer
   // that should be valid throughout this object's lifetime.
   // |request| is also not owned by this and is guaranteed to outlive dialog.
   // Neither |request| or |dialog| should be null.
   PaymentRequestSheetController(PaymentRequest* request,
-                                PaymentRequestDialogView* dialog)
-      : request_(request), dialog_(dialog) {
-    DCHECK(request_);
-    DCHECK(dialog_);
-  }
-  virtual ~PaymentRequestSheetController() {}
+                                PaymentRequestDialogView* dialog);
+  ~PaymentRequestSheetController() override {}
 
   virtual std::unique_ptr<views::View> CreateView() = 0;
 
   // The PaymentRequest object associated with this instance of the dialog.
   // Caller should not take ownership of the result.
   PaymentRequest* request() { return request_; }
 
   // The dialog that contains and owns this object.
   // Caller should not take ownership of the result.
   PaymentRequestDialogView* dialog() { return dialog_; }
 
+ protected:
+  // Creates and returns the primary action button for this sheet. It's
+  // typically a blue button with the "Pay" or "Done" labels. Subclasses may
+  // return an empty std::unique_ptr (nullptr) to indicate that no primary
+  // button should be displayed. The caller takes ownership of the button but
+  // the view is guaranteed to be outlived by the controller so subclasses may
+  // retain a raw pointer to the returned button (for example to control its
+  // enabled state).
+  virtual std::unique_ptr<views::Button> CreatePrimaryButton();
+
+  // views::VectorIconButtonDelegate:
+  void ButtonPressed(views::Button* sender, const ui::Event& event) override;
+
+  // Creates a view to be displayed in the PaymentRequestDialog.
+  // |header_view| is the view displayed on top of the dialog, containing title,
+  // (optional) back button, and close buttons.
+  // |content_view| is displayed between |header_view| and the pay/cancel
+  // buttons. Also adds the footer, returned by CreateFooterView(), which is
+  // clamped to the bottom of the containing view.  The returned view takes
+  // ownership of |header_view|, |content_view|, and the footer.
+  // +---------------------------+
+  // |        HEADER VIEW        |
+  // +---------------------------+
+  // |          CONTENT          |
+  // |           VIEW            |
+  // +---------------------------+
+  // |            | CANCEL | PAY | <-- footer
+  // +---------------------------+
+  std::unique_ptr<views::View> CreatePaymentView(
+      std::unique_ptr<views::View> header_view,
+      std::unique_ptr<views::View> content_view);
+
+  // Creates the row of button containing the Pay, cancel, and extra buttons.
+  // |controller| is installed as the listener for button events.
+  std::unique_ptr<views::View> CreateFooterView();
+
  private:
   // Not owned. Will outlive this.
   PaymentRequest* request_;
   // Not owned. Will outlive this.
   PaymentRequestDialogView* dialog_;
 
   DISALLOW_COPY_AND_ASSIGN(PaymentRequestSheetController);
 };
 
 }  // namespace payments
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_SHEET_CONTROLLER_H_