Per webgpu spec:

When updating the rendering of a WebGPU canvas (an HTMLCanvasElement or an OffscreenCanvas with a placeholder canvas element) with a GPUCanvasContext context, which occurs before getting the canvas’s image contents

but this is not happening in servo:

GetCurrentTexture
canvas_data_source
update_rendering_of_webgpu_canvas
send_swap_chain_present
GetCurrentTexture
canvas_data_source
update_rendering_of_webgpu_canvas
send_swap_chain_present

I think update_rendering_of_webgpu_canvas should happen before canvas_data_source. cc @gterzian

I think update_rendering_of_webgpu_canvas should happen before canvas_data_source.

As per the spec, I think we should do layout only at the end of the "update the rendering", but currently we do it in multiple places, and problably also before update_rendering_of_webgpu_canvas is called into. canvas_data_source is called as part of layout right?

I think update_rendering_of_webgpu_canvas should happen before canvas_data_source.

As per the spec, I think we should do layout only at the end of the "update the rendering", but currently we do it in multiple places, and problably also before update_rendering_of_webgpu_canvas is called into. canvas_data_source is called as part of layout right?

I think so. We cannot really fix HTML event loop integration of webgpu until HTML event loop is fixed.

Closed in favor of #34631