Changelog for WebGPU in Chromium / Dawn 98

Hey all,

You can find the details of the updates in this document
<https://hackmd.io/atgdYZUHTZmoIrpfF3gJaQ?view>. Below is the introduction
of it for context.

Chromium’s WebGPU implementation and Dawn’s API try to closely follow
changes to the WebGPU specification. When the WebGPU IDL changes, Chromium
and Dawn will try to support both the deprecated and the new version of the
IDL at the same time so prototypes can be updated. In JavaScript, uses of
the deprecated path will result in a console warning, while when using Dawn
directly, the deprecated path will print a warning to stderr.

Note that all changes to Dawn’s API make it closer to webgpu.h that we hope
will allow applications to target both Dawn, and wgpu in native before
being compiled in WASM. Emscripten will also be updated from the “old” to
the “new” API but won’t have a smooth transition since developers control
which version of emscripten they use.

Items deprecated in this changelog will be removed in the next branched
version of Chromium. They will also be removed in Chromium Canary and top
of tree Dawn two weeks after this changelog is published in Canary and top
of tree Dawn (so starting 2022-01-05).

Cheers,

Corentin