Adds a conversion function on List<JSAny?> so that users can
modify the original list and have those changes carry forward
to the array. Creates a proxy object for dart2wasm when the
list is not a JSArrayImpl. This proxy uses handler methods and
the fact that Array methods are generic to provide an Array
interface. Also fixes a small issue in the exporting so that
toJS'd function types have a valid return type.
CoreLibraryReviewExempt: Backend-specific library.
Change-Id: I00f453aa82dd19f2913820579eb2675b799288d3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/323446
Commit-Queue: Srujan Gaddam <srujzs@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Srujan Gaddam
fedc687bd3