[Web Payments] Let subsheets define the initial focus

chrome/browser/ui/views/payments/cvc_unmask_view_controller.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_PAYMENTS_CVC_UNMASK_VIEW_CONTROLLER_H_
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_CVC_UNMASK_VIEW_CONTROLLER_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 67 matching lines @@
   base::string16 GetSheetTitle() override;
   void FillContentView(views::View* content_view) override;
   std::unique_ptr<views::Button> CreatePrimaryButton() override;
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
  private:
   // Called when the user confirms their CVC. This will pass the value to the
   // active FullCardRequest.
   void CvcConfirmed();
 
+  views::View* GetFirstFocusedView() override;
+
   views::Textfield* cvc_field_;  // owned by the view hierarchy, outlives this.
   autofill::CreditCard credit_card_;
   content::WebContents* web_contents_;
   // The identity provider, used for Payments integration.
   std::unique_ptr<IdentityProvider> identity_provider_;
   autofill::payments::PaymentsClient payments_client_;
   autofill::payments::FullCardRequest full_card_request_;
   base::WeakPtr<autofill::CardUnmaskDelegate> unmask_delegate_;
 
   base::WeakPtrFactory<CvcUnmaskViewController> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CvcUnmaskViewController);
 };
 
 }  // namespace payments
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_CVC_UNMASK_VIEW_CONTROLLER_H_