As usual, also bump its helper crates (`js-sys`, `web-sys` and
`wasm-bindgen-futures`) to the latest versions.
Due to https://github.com/rustwasm/wasm-bindgen/pull/3031, use the
`serde-wasm-bindgen` crate as a replacement to the deprecated
`JsValue::from_serde` function.
* avm2: Implement `BitmapData.draw` for `wgpu` backend
This method requires us to have the ability to render directly to a
texture. Fortunately, the `wgpu` backend already supports this in
the form of `TextureTarget`. However, the rendering code required
some refactoring in order to avoid creating duplicate `wgpu` resources.
The current implementation blocks on copying the pixels back
from the GPU to the CPU, so that we can immediately set them in
the Ruffle `BitmapData`. This is likely very inefficient, but will
work for a first implementation.
In the future, we could explore allowing the CPU image data and GPU
texture to be out of sync, and only synchronized when explicitly
necessary (e.g. on `getPixel` or `setPixel` calls).
* Rename `with_offscreen_backend` to `render_offscreen` and use Bitmap
* Don't panic when backend doesn't implement `render_offscreen`
It was only used to make structs `#[derive(gc_arena::Collect)]`, and
generally it doesn't make much sense that `render` needs to be GC-aware.
So instead annotate `render` fields in `core` with `#[collect(require_static)]`.