As in topic. API currently offers fixed ratio only for Mac but not for Windows
shell/browser/native_window_views.cc
NotifyWindowMove();
}
void NativeWindowViews::HandleKeyboardEvent(
    content::WebContents*,
    const content::NativeWebKeyboardEvent& event) {
#if defined(OS_LINUX)
  if (event.windows_key_code == ui::VKEY_BROWSER_BACK)
    NotifyWindowExecuteAppCommand(kBrowserBackward);
  else if (event.windows_key_code == ui::VKEY_BROWSER_FORWARD)
    NotifyWindowExecuteAppCommand(kBrowserForward);
#endif
  keyboard_event_handler_->HandleKeyboardEvent(event,
                                               root_view_->GetFocusManager());
  root_view_->HandleKeyEvent(event);
}
#if defined(OS_LINUX)
void NativeWindowViews::OnMouseEvent(ui::MouseEvent* event) {
  if (event->type() != ui::ET_MOUSE_PRESSED)
    return;
  if (event->changed_button_flags() == ui::EF_BACK_MOUSE_BUTTON)
    NotifyWindowExecuteAppCommand(kBrowserBackward);
  else if (event->changed_button_flags() == ui::EF_FORWARD_MOUSE_BUTTON)
    NotifyWindowExecuteAppCommand(kBrowserForward);
}
#endif
ui::WindowShowState NativeWindowViews::GetRestoredState() {