Use ViewStack to convert card upload request CVC experiment to 2-step flow

chrome/browser/ui/views/autofill/save_card_bubble_views.h

 // Copyright 2015 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_AUTOFILL_SAVE_CARD_BUBBLE_VIEWS_H_
 #define CHROME_BROWSER_UI_VIEWS_AUTOFILL_SAVE_CARD_BUBBLE_VIEWS_H_
 
 #include "base/macros.h"
 #include "chrome/browser/ui/autofill/save_card_bubble_view.h"
 #include "chrome/browser/ui/views/location_bar/location_bar_bubble_delegate_view.h"
+#include "chrome/browser/ui/views/payments/view_stack.h"
 #include "components/autofill/core/browser/ui/save_card_bubble_controller.h"
 #include "ui/views/controls/link_listener.h"
 #include "ui/views/controls/styled_label_listener.h"
 #include "ui/views/controls/textfield/textfield_controller.h"
 
 namespace content {
 class WebContents;
 }
 
 namespace views {
@@ skipping 57 matching lines @@
   ~SaveCardBubbleViews() override;
 
   std::unique_ptr<views::View> CreateMainContentView();
   std::unique_ptr<views::View> CreateRequestCvcView();
 
   // views::BubbleDialogDelegateView
   void Init() override;
 
   SaveCardBubbleController* controller_;  // Weak reference.
 
-  views::Textfield* cvc_textfield_;
+  ViewStack* view_stack_ = nullptr;
 
-  views::Link* learn_more_link_;
+  views::Textfield* cvc_textfield_ = nullptr;
+
+  views::Link* learn_more_link_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(SaveCardBubbleViews);
 };
 
 }  // namespace autofill
 
 #endif  // CHROME_BROWSER_UI_VIEWS_AUTOFILL_SAVE_CARD_BUBBLE_VIEWS_H_