[Web Payments] Implement proper focusing in Payment Request

chrome/browser/ui/views/payments/payment_request_sheet_controller.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_SHEET_CONTROLLER_H_
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_SHEET_CONTROLLER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 74 matching lines @@
   // +---------------------------+
   virtual std::unique_ptr<views::View> CreateExtraFooterView();
 
   // views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
   // Creates the row of button containing the Pay, cancel, and extra buttons.
   // |controller| is installed as the listener for button events.
   std::unique_ptr<views::View> CreateFooterView();
 
+  // Returns the view that should be initially focused on this sheet. Typically,
+  // this returns the primary button if it's enabled or the secondary button
+  // otherwise. Subclasses may return a different view if they need focus to
+  // start off on a different view (a textfield for example). This will only be
+  // called after the view has been completely created through calls to
+  // CreatePaymentView and related functions.
+  virtual views::View* GetFirstFocusedView();
+
  private:
   // Creates a view to be displayed in the PaymentRequestDialog.
   // |header_view| is the view displayed on top of the dialog, containing title,
   // (optional) back button, and close buttons.
   // |content_view| is displayed between |header_view| and the pay/cancel
   // buttons. Also adds the footer, returned by CreateFooterView(), which is
   // clamped to the bottom of the containing view.  The returned view takes
   // ownership of |header_view|, |content_view|, and the footer.
   // +---------------------------+
   // |        HEADER VIEW        |
@@ skipping 11 matching lines @@
   PaymentRequestDialogView* dialog_;
 
   // This view is owned by its encompassing ScrollView.
   views::View* pane_;
   views::View* content_view_;
 
   // Hold on to the ScrollView because it must be explicitly laid out in some
   // cases.
   std::unique_ptr<views::ScrollView> scroll_;
 
+  // Hold on to the primary and secondary buttons to use them as initial focus
+  // targets when subclasses don't want to focus anything else.
+  std::unique_ptr<views::Button> primary_button_;
+  std::unique_ptr<views::Button> secondary_button_;
+
   DISALLOW_COPY_AND_ASSIGN(PaymentRequestSheetController);
 };
 
 }  // namespace payments
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_PAYMENT_REQUEST_SHEET_CONTROLLER_H_