[Web Payments] Let subsheets define the initial focus

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

Index: chrome/browser/ui/views/payments/editor_view_controller.h
diff --git a/chrome/browser/ui/views/payments/editor_view_controller.h b/chrome/browser/ui/views/payments/editor_view_controller.h
index ec792873ff2893e2abe30538a9ed89669ef12846..402d6673a1b636747967ddb08d8a7753337f72a7 100644
--- a/chrome/browser/ui/views/payments/editor_view_controller.h
+++ b/chrome/browser/ui/views/payments/editor_view_controller.h
@@ -134,6 +134,7 @@ class EditorViewController : public PaymentRequestSheetController,
  private:
   // PaymentRequestSheetController:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
+  views::View* GetFirstFocusedView() override;
 
   // views::TextfieldController:
   void ContentsChanged(views::Textfield* sender,
@@ -158,6 +159,9 @@ class EditorViewController : public PaymentRequestSheetController,
   // 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);
 };