mac: window.close() breaks the cefclient with --hide-window-on-close

[nik-sp]

Description

When using the window.close() method in the cefclient application on macOS with the --hide-window-on-close flag enabled, the application breaks. The page is rendered white, it's impossible to close the application.

To Reproduce

Steps to reproduce the behavior:

1. Launch the cefclient application with the --hide-window-on-close flag enabled.
2. Navigate within the application to a webpage where window.close() is invoked.
3. Invoke window.close() programmatically or through an action in the webpage.
4. Notice that the window is close, but the app still present in the dock

Expected behavior

The application should gracefully close the window or hide it according to the --hide-window-on-close flag setting, without breaking or exhibiting unexpected behavior when window.close() is invoked.

Screenshots

With hidden frame

Versions (please complete the following information):

• OS: MacOS 14.3.1
• CEF Version: 121, 122 and latest main

Additional context

It seems that CloseWithReason exits prematurely because OnWindowCloseRequested returns CloseRequestResult::kCannotClose. As a result, the application ends up in an invalid partially closed state.

void Widget::CloseWithReason(ClosedReason closed_reason) {
  if (widget_closed_) {
    // It appears we can hit this code path if you close a modal dialog then
    // close the last browser before the destructor is hit, which triggers
    // invoking Close again.
    return;
  }
  if (block_close_) {
    return;
  }
  if (non_client_view_ && non_client_view_->OnWindowCloseRequested() ==
                              CloseRequestResult::kCannotClose) {
    return;
  }