[imgui-glutin-support] get_frame_size: Pass immutable Window
There is no reason to pass an immutable window, as the function does not
mutate it.
@@ -223,7 +223,7 @@ pub fn update_mouse_cursor(imgui: &ImGui, window: &Window) {
/// Get the current frame size for imgui frame rendering.
///
/// Returns `None` if the window no longer exists
-pub fn get_frame_size(window: &mut Window) -> Option<FrameSize> {
+pub fn get_frame_size(window: &Window) -> Option<FrameSize> {
window.get_inner_size().map(|logical_size| FrameSize {
logical_size: logical_size.into(),
hidpi_factor: window.get_hidpi_factor(),
