TL;DR: Lots of breaking changes to catch up to the spec. Some new features (like create pipeline async). Lots of behind-the-scenes improvements towards an Origin Trial.
You can find the details of the updates in this document
. 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, as best as possible Chromium and Dawn will support both the “old” and the “new” version of the IDL at the same time so prototypes can be updated. In JS, uses of the “old” path will result in a console warning, while when using Dawn directly, the “old” 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.
A couple weeks after an update like this one, the “old” version will be removed. This means that the “old” version of the items below will start being removed from Chromium/Dawn starting on 2021-04-21.