@deprecate dart:html and other "legacy" DOM libraries

[kevmoo]

We'd like to fully remove these in 2025. Having them deprecated with a year lead time is a good idea.

• dart:html
• dart:indexed_db
• dart:js
• dart:js_util
• dart:svg
• dart:web_audio
• dart:web_gl

[srujzs]

I'd adjust expectations here: removing them will be a lot longer process (unless we're treating internal vs external usage differently), but starting the deprecation process is good.

[ahmednfwela]

first of all this issue has to be addressed dart-lang/web#252 before considering deprecating any API, it affects Eventlistener and other interfaces, which affects ALL dom elements, making it a high impact issue

[r-durao-pvotal]

This is a great initiative IMO.

I would be curious to see though how many libraries that the Dart and Flutter team maintain (not to mention everyone else) that still use the mentioned libraries (grpc lib comes to mind) and how that may affect the proposed timeline.

[vd3d]

BTW, having js_interop working on desktop (ie. having an internal JS engine, would be great for compatibility) ;-)

[osa1]

Closing as these libraries were deprecated a while ago in f3b6370.

(We also have a duplicate of this: #59716)