Original change: https://dart-review.googlesource.com/c/sdk/+/366963
This reverts commit 72b2883c6f.
[js_runtime, js_dev_runtime] Implement `microsecond` field of `DataTime`
- Move DateTime implementation for dart2js and DDC into a shared place to reduce duplication.
- Add a _microsecond field to the web DateTime to track microseconds outside of the JavaScript Date.
- The cute dart2js optimization whereby `DateTime.now().millisecondsSinceEpoch` is compiled to `Date.now()` still works.
- Both implementations report better errors.
- Fixed VM bug with in-range sentinel.
Issue: https://github.com/dart-lang/sdk/issues/44876
Issue: https://github.com/firebase/flutterfire/issues/12102
Issue: b/342552853
CoreLibraryReviewExempt: Reapply of unchanged code
Change-Id: I7f14b69e412a052ef3fe6b43cc9cf9d96319adb8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/368380
Commit-Queue: Stephen Adams <sra@google.com>
Reviewed-by: Lasse Nielsen <lrn@google.com>
20316bcc5b