pub fn start_webgpu_thread(
compositor_api: CrossProcessCompositorApi,
webrender_external_image_id_manager: WebRenderExternalImageIdManager,
wgpu_image_map: WebGpuExternalImageMap,
) -> Option<(WebGPU, IpcReceiver<WebGPUMsg>)>pub fn start_webgpu_thread(
compositor_api: CrossProcessCompositorApi,
webrender_external_image_id_manager: WebRenderExternalImageIdManager,
wgpu_image_map: WebGpuExternalImageMap,
) -> Option<(WebGPU, IpcReceiver<WebGPUMsg>)>