* 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
