toJS conversions of Dart typed lists create a new typed array even if typed list was a wrapper from toDart

[srujzs]

On dart2wasm, when toJS is called, we check if the typed list was a wrapper. If so, we call toJSArrayExternRef:

sdk/sdk/lib/_internal/wasm/lib/js_interop_patch.dart

Line 458 in 27e8a4a

@patch

. Otherwise, we clone:

sdk/sdk/lib/_internal/wasm/lib/js_helper_patch.dart

Line 397 in 96ca861

WasmExternRef jsFloat32ArrayFromDartFloat32List(Float32List l) {

.

However, toJSArrayExternRef creates a new typed array using the existing buffer:

sdk/sdk/lib/_internal/wasm/lib/js_typed_array.dart

Line 2235 in 96ca861

@override

.

This then leads to equality check failures between a and a.toDart.toJS. For that reason and consistency with how we handle List/JSArray conversions, we should return the original typed array. This also makes the a.toDart.toJS consistent with the JS compilers.