[Payments] Improve the closing of the PR dialog.

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

 // 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.
 
 #include "chrome/browser/ui/views/payments/test_chrome_payment_request_delegate.h"
 
+#include <utility>
+
 #include "content/public/browser/web_contents.h"
+#include "ui/views/widget/widget.h"
+#include "ui/views/widget/widget_observer.h"
 
 namespace payments {
 
 TestChromePaymentRequestDelegate::TestChromePaymentRequestDelegate(
     content::WebContents* web_contents,
-    PaymentRequestDialog::ObserverForTest* observer)
-    : ChromePaymentRequestDelegate(web_contents), observer_(observer) {}
+    PaymentRequestDialogView::ObserverForTest* observer,
+    views::WidgetObserver* widget_observer)
+    : ChromePaymentRequestDelegate(web_contents),
+      observer_(observer),
+      widget_observer_(widget_observer) {}
 
-void TestChromePaymentRequestDelegate::ShowPaymentRequestDialog(
-    PaymentRequest* request) {
-  PaymentRequestDialog::ShowWebModalPaymentDialog(
-      new PaymentRequestDialog(request, observer_), request);
+void TestChromePaymentRequestDelegate::ShowDialog(PaymentRequest* request) {
+  PaymentRequestDialogView* dialog_view =
+      new PaymentRequestDialogView(request, observer_);
+  dialog_view->ShowDialog();
+
+  // The widget is now valid, so register its observer.
+  views::Widget* widget = dialog_view->GetWidget();
+  widget->AddObserver(widget_observer_);
+
+  dialog_ = std::move(dialog_view);
 }
 
 }  // namespace payments