Update the Canvas2d Layer proposal to support filters.

[graveljp]

No description provided.

[Kaiido]

Glad to see this moving again.
I left a few suggested edits that only deal with the few typos I found while reading the changes, I hope it's fine with everyone.
I'll leave my comments about the main design in other issues when it's time.

[tomayac]

Sorry, but it wasn’t clear to me: Will this still support CanvasFilter?

[fserb]

Yes. Sorry it wasn't clear. We are going to give a bit more context on the WhatWG issue next week. But this was agreed between the browsers as the proper way to surface CanvasFilter.

[graveljp]

This is already covered in this pull request:

"Filters can be specified as a string parsable as a <filter-value-list>, or as a CanvasFilter object (when that proposal lands)."

I said "when that proposal lands", because as of right now, the CanvasFilter proposal has been reverted from the specification. See discussion in whatwg/html#5621 and revert CL at whatwg/html@c7ad099. The main objections were around the use of ctx.filter, which has never reached consensus. This new beginLayer proposal should resolve these concerns.

[tomayac]

Brilliant, thanks for clarifying! Glad CanvasFilter has found a new home.