* refactor: add a wrapper for wrangling uv handles.
Part 1 of a fix for #25248, #22069.
Place the uv_asyncs owned by NodeBindings, ElectronBindings inside a new
UvHandle wrapper class which manages uv_handles' need for their closed()
callback to be invoked before the handles' memory can be freed.
* chore: make lint happy
* refactor: use DCHECK_EQ() instead of DCHECK()
* refactor: fix oops
* refactor: use gin in Promise
* refactor: separate Promise impl that returns nothing
* refactor: use Promise<void> for promise that returns nothing
* fix: methods should be able to run on both browser and renderer process
* fix: should not pass base::StringPiece across threads
* refactor: no more need to use different ResolvePromise for empty Promise
* refactor: move Promise to gin_helper
* refactor: make util::Promise type safe when chaining in native
* fixup! refactor: make util::Promise type safe when chaining in native
* chore: remove spare brackets