Fixes https://github.com/dart-lang/sdk/issues/60644
Previously, we made no special case for JSBoxedDartObjects, so isA
would always return true for any object (as JSBoxedDartObject contains
an @JS('Object') annotation). This is not obvious however, and it's
much more useful to check that the value is a result of a previous
`toJSBox` call. Documentation is updated/cleaned up to make note of
the various exceptions in `isA`.
CoreLibraryReviewExempt: Web-only library.
Change-Id: Ibd8873d3f862f4c950101f5f049327a1aa5c7bf2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/445522
Commit-Queue: Srujan Gaddam <srujzs@google.com>
Reviewed-by: Ömer Ağacan <omersa@google.com>
Reviewed-by: Leaf Petersen <leafp@google.com>
Srujan Gaddam
d672d98636