[Web Payments] Let subsheets define the initial focus

chrome/browser/ui/views/payments/editor_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_EDITOR_VIEW_CONTROLLER_H_
 #define CHROME_BROWSER_UI_VIEWS_PAYMENTS_EDITOR_VIEW_CONTROLLER_H_
 
 #include <map>
 #include <memory>
 #include <tuple>
@@ skipping 116 matching lines @@
 
   // Update the editor view by removing all it's child views and recreating
   // the input fields returned by GetFieldDefinitions. Note that
   // CreateEditorView MUST have been called at least once before calling
   // UpdateEditorView.
   virtual void UpdateEditorView();
 
  private:
   // PaymentRequestSheetController:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
+  views::View* GetFirstFocusedView() override;
 
   // views::TextfieldController:
   void ContentsChanged(views::Textfield* sender,
                        const base::string16& new_contents) override;
 
   // Creates the whole editor view to go within the editor dialog. It
   // encompasses all the input fields created by CreateInputField().
   std::unique_ptr<views::View> CreateEditorView();
 
   // Adds some views to |layout|, to represent an input field and its labels.
   // |field| is the field definition, which contains the label and the hint
   // about the length of the input field. A placeholder error label is also
   // added (see implementation).
   void CreateInputField(views::GridLayout* layout, const EditorField& field);
 
   // Used to remember the association between the input field UI element and the
   // original field definition. The ValidatingTextfield* and ValidatingCombobox*
   // are owned by their parent view, this only keeps a reference that is good as
   // long as the input field is visible.
   TextFieldsMap text_fields_;
   ComboboxMap comboboxes_;
   // Tracks the relationship between a field and its error label.
   ErrorLabelMap error_labels_;
 
+  // The first label in the editor, used to set the initial focus.
+  views::View* first_field_view_;
+
   DISALLOW_COPY_AND_ASSIGN(EditorViewController);
 };
 
 }  // namespace payments
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PAYMENTS_EDITOR_VIEW_CONTROLLER_H_