This is a re-land of 152cc24, which has been reverted in 3f9ae7. Unlike
the original change, this doesn't alter the `dart:_wasm` library.
We can revisit an API split to remove `js_interop` APIs there once the
standalone target has progressed further.
Original change's description:
> [dart2wasm] Split patch files by whether they use JS interop
>
> The eventual goal of the `dart2wasm_standalone` platform is to not rely
> on a JavaScript environment, which requires rewriting everything that
> currently relies on `js_interop` or `JS()` helpers.
>
> Since most of the patches are still written in Dart and we don't want
> to duplicate that code for the standalone target, this splits patch
> files by whether they rely on JS-interop or not. The main entrypoint
> for each patch (e.g. `lib/_internal/wasm/lib/core_patch.dart`) no
> longer relies on JS-interop and can safely be used in the standalone
> target. Part files that previously needed to use JS-interop have been
> moved into separate patches now, which allows us to migrate them
> incrementally.
>
> In some cases, it was easier to add new patch files:
>
> - Similar to the split between `boxed_int` and the `toString` helper
> patch, we now have the same for `boxed_double`.
> - The functionality to copy from JS typed data wrappers into Dart typed
> lists wouldn't work with standalone, so I've moved it into a separate
> method we can patch to be a noop.
> - `dart:_wasm` exposes APIs to convert between `JSAny` and `externref`.
> This is part of a public API, but I had to move those declarations
> into a patch file because they wouldn't work with standalone.
> Arguably, a separate library (`dart:_wasm_js_interop`?) would be
> cleaner but it might be fine as long as `dart:_wasm` is experimental?
>
> For now, new patch files relying on JS interop are also applied to the
> standalone target. They are marked with a comment indicating that they
> need to be migrated though.
Cq-Include-Trybots: luci.dart.try:flutter-analyze-try
Change-Id: I98a628f96cba7e0f0af7e86e058cda43c2c73898
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/495302
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Simon Binder
0ae4f93e29