[Web Payments] Implement proper focusing in Payment Request

chrome/browser/ui/views/payments/payment_request_dialog_view.cc

Index: chrome/browser/ui/views/payments/payment_request_dialog_view.cc
diff --git a/chrome/browser/ui/views/payments/payment_request_dialog_view.cc b/chrome/browser/ui/views/payments/payment_request_dialog_view.cc
index de74d3d2fb21ca3c8bc975ddd53e992875dc9cc4..8752e2a8ee51a900ea1c8345c74063e4743cbb2f 100644
--- a/chrome/browser/ui/views/payments/payment_request_dialog_view.cc
+++ b/chrome/browser/ui/views/payments/payment_request_dialog_view.cc
@@ -86,6 +86,10 @@ ui::ModalType PaymentRequestDialogView::GetModalType() const {
   return ui::MODAL_TYPE_CHILD;
 }
 
+views::View* PaymentRequestDialogView::GetInitiallyFocusedView() {
+  return view_stack_.get();
+}
+
 bool PaymentRequestDialogView::Cancel() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   // Called when the widget is about to close. We send a message to the