[DX9] Some games do not reset at window resizing

[Godnoken]

• Warhammer 40K: Dawn of War; Displays ImGui fine if injected on launch, but if you change resolution in-game then ImGui disappears due to no trigger of a device reset.
• Heroes of Might & Magic 5; If injected on launch, ImGui doesn't show up & resolution change doesn't trigger device reset

The solution could be to save the previous size & check if it changes on each frame. Since we already call get_window_rect, hopefully that is enough, but it could very well be so that the device's viewport needs to be checked as well like in the OpenGL solution.

Since this is a fairly isolated thing, I'm wondering - Is the overhead of checking the viewport basically non-existent or is it something that has to be considered?

---

There is also another game (don't remember which one) with a similar issue. Might even have been a DirectDraw game that I ran with dxwrapper, so I'm not too sure of the relevancy here since it may be so that there is no equivalent to Reset in those games.

The only solution I could come up with was to read for calls to WM_ACTIVATEAPP and subsequently reset the device manually from there.

 WM_ACTIVATEAPP => {
            if let Some(device) = D3D9DEVICE.get() {
                let mut present_params = D3DPRESENT_PARAMETERS {
                    Windowed: BOOL(1),
                    SwapEffect: D3DSWAPEFFECT_DISCARD,
                    BackBufferFormat: D3DFMT_UNKNOWN,
                    ..core::mem::zeroed()
                };
                device.Reset(&mut present_params).unwrap();
            }
        }

It's not the prettiest solution & would require us to expose the device somehow like talked about in #80