[Payments] Add a Pay button in the Order summary screen

chrome/browser/ui/views/payments/payment_request_dialog_view.cc

 // 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.
 
 #include "chrome/browser/ui/views/payments/payment_request_dialog_view.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 47 matching lines @@
   ShowInitialPaymentSheet();
 }
 
 PaymentRequestDialogView::~PaymentRequestDialogView() {}
 
 ui::ModalType PaymentRequestDialogView::GetModalType() const {
   return ui::MODAL_TYPE_CHILD;
 }
 
 bool PaymentRequestDialogView::Cancel() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   // Called when the widget is about to close. We send a message to the
-  // PaymentRequest object to signal user cancellation.
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  // PaymentRequest object to signal user cancellation. Before destroying the
+  // PaymentRequest object, we destroy all controllers so that they are not left
+  // alive with an invalid PaymentRequest pointer.
+  controller_map_.clear();
   request_->UserCancelled();
   return true;
 }
 
 bool PaymentRequestDialogView::ShouldShowCloseButton() const {
   // Don't show the normal close button on the dialog. This is because the
   // typical dialog header doesn't allow displaying anything other that the
   // title and the close button. This is insufficient for the PaymentRequest
   // dialog, which must sometimes show the back arrow next to the title.
   // Moreover, the title (and back arrow) should animate with the view they're
@@ skipping 52 matching lines @@
   if (observer_for_testing_)
     observer_for_testing_->OnCreditCardEditorOpened();
 }
 
 void PaymentRequestDialogView::ShowDialog() {
   constrained_window::ShowWebModalDialogViews(this, request_->web_contents());
 }
 
 void PaymentRequestDialogView::CloseDialog() {
   // This calls PaymentRequestDialogView::Cancel() before closing.
+  // ViewHierarchyChanged() also gets called after Cancel().
   GetWidget()->Close();
 }
 
 void PaymentRequestDialogView::ShowInitialPaymentSheet() {
   view_stack_.Push(
       CreateViewAndInstallController(
           base::MakeUnique<PaymentSheetViewController>(request_, this),
           &controller_map_),
       /* animate = */ false);
   if (observer_for_testing_)
     observer_for_testing_->OnDialogOpened();
 }
 
 gfx::Size PaymentRequestDialogView::GetPreferredSize() const {
   return gfx::Size(450, 450);
 }
 
 void PaymentRequestDialogView::ViewHierarchyChanged(
     const ViewHierarchyChangedDetails& details) {
   // When a view that is associated with a controller is removed from this
   // view's descendants, dispose of the controller.
   if (!details.is_add &&
       controller_map_.find(details.child) != controller_map_.end()) {
     DCHECK(!details.move_view);
     controller_map_.erase(details.child);
   }
 }
 
 }  // namespace payments