[Payments] Introduce basic interactive browsertests for Payment Request

chrome/browser/ui/views/payments/payment_request_dialog.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_DIALOG_H_
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_DIALOG_H_
 
 #include <map>
 #include <memory>
 
@@ skipping 10 matching lines @@
 // PaymentRequestDialog is responsible for listening for those views being
 // removed from the hierarchy and delete the associated controllers.
 using ControllerMap =
     std::map<views::View*, std::unique_ptr<PaymentRequestSheetController>>;
 
 // The dialog delegate that represents a desktop WebPayments dialog. This class
 // is responsible for displaying the view associated with the current state of
 // the WebPayments flow and managing the transition between those states.
 class PaymentRequestDialog : public views::DialogDelegateView {
  public:
-  explicit PaymentRequestDialog(PaymentRequest* request);
+  class ObserverForTest {
+   public:
+    virtual void OnDialogOpened() = 0;
+  };
+
+  // Build a Dialog around the PaymentRequest object. |observer| is used to
+  // be notified of dialog events as they happen (but may be NULL) and should
+  // outlive this object.
+  PaymentRequestDialog(PaymentRequest* request,
+                       PaymentRequestDialog::ObserverForTest* observer);
   ~PaymentRequestDialog() override;
 
   // views::WidgetDelegate
   ui::ModalType GetModalType() const override;
 
   // views::DialogDelegate
   bool Cancel() override;
   bool ShouldShowCloseButton() const override;
   int GetDialogButtons() const override;
 
   void GoBack();
   void ShowOrderSummary();
   void ShowPaymentMethodSheet();
   void CloseDialog();
 
+  static void ShowWebModalPaymentDialog(PaymentRequestDialog* dialog,
+                                        PaymentRequest* request);
+
  private:
   void ShowInitialPaymentSheet();
 
   // views::View
   gfx::Size GetPreferredSize() const override;
   void ViewHierarchyChanged(const ViewHierarchyChangedDetails& details)
       override;
 
   // Non-owned reference to the PaymentRequest that initiated this dialog. Since
   // the PaymentRequest object always outlives this one, the pointer should
   // always be valid even though there is no direct ownership relationship
   // between the two.
   PaymentRequest* request_;
+  // May be null.
+  ObserverForTest* observer_;
   ControllerMap controller_map_;
   ViewStack view_stack_;
 
   DISALLOW_COPY_AND_ASSIGN(PaymentRequestDialog);
 };
 
 }  // namespace payments
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_DIALOG_H_