Ensure default dialog button focus remains after a dialog update.

ui/views/window/dialog_client_view_unittest.cc

Index: ui/views/window/dialog_client_view_unittest.cc
diff --git a/ui/views/window/dialog_client_view_unittest.cc b/ui/views/window/dialog_client_view_unittest.cc
index bb8ec3647fdd6cf49ca65a1934b3cc2727ab9e95..3d933752f6a8a31467bfcf9a9cb069c0bac4e1ae 100644
--- a/ui/views/window/dialog_client_view_unittest.cc
+++ b/ui/views/window/dialog_client_view_unittest.cc
@@ -141,6 +141,8 @@ class DialogClientViewTest : public test::WidgetTest,
 
   DialogClientView* client_view() { return client_view_; }
 
+  Widget* widget() { return widget_; }
+
  private:
   // The dialog Widget.
   Widget* widget_ = nullptr;
@@ -436,4 +438,31 @@ TEST_F(DialogClientViewTest, ButtonPosition) {
             height() + client_view()->ok_button()->y());
 }
 
+// Ensures that the focus of the button remains after a dialog update.
+TEST_F(DialogClientViewTest, FocusUpdate) {
+  // Test with just an ok button.
+  widget()->Show();
+  SetDialogButtons(ui::DIALOG_BUTTON_OK);
+  EXPECT_FALSE(client_view()->ok_button()->HasFocus());
+  client_view()->ok_button()->RequestFocus();  // Set focus.
+  EXPECT_TRUE(client_view()->ok_button()->HasFocus());
+  client_view()->UpdateDialogButtons();
+  EXPECT_TRUE(client_view()->ok_button()->HasFocus());
+}
+
+// Ensures that the focus of the button remains after a dialog update that
+// contains multiple buttons.
+TEST_F(DialogClientViewTest, FocusMultipleButtons) {
+  // Test with ok and cancel buttons.
+  widget()->Show();
+  SetDialogButtons(ui::DIALOG_BUTTON_CANCEL | ui::DIALOG_BUTTON_OK);
+  EXPECT_FALSE(client_view()->ok_button()->HasFocus());
+  EXPECT_FALSE(client_view()->cancel_button()->HasFocus());
+  client_view()->cancel_button()->RequestFocus();  // Set focus.
+  EXPECT_FALSE(client_view()->ok_button()->HasFocus());
+  EXPECT_TRUE(client_view()->cancel_button()->HasFocus());
+  client_view()->UpdateDialogButtons();
+  EXPECT_TRUE(client_view()->cancel_button()->HasFocus());
+}
+
 }  // namespace views