Re-enable some wasm tests which have been fixed now. (flutter/engine#40931)

Re-enable some wasm tests which have been fixed now.

engine/src/flutter/lib/web_ui/lib/src/engine/canvaskit/image_web_codecs.dart

@@ -14,6 +14,7 @@ import 'dart:js_interop';
 import 'dart:math' as math;
 import 'dart:typed_data';
 
+import 'package:js/js.dart';
 import 'package:meta/meta.dart';
 import 'package:ui/ui.dart' as ui;
 
@@ -439,12 +440,24 @@ bool _shouldReadPixelsUnmodified(VideoFrame videoFrame, ui.ImageByteFormat forma
   return format == ui.ImageByteFormat.rawRgba && isRgbFrame;
 }
 
+@JS('Uint8Array')
+@staticInterop
+class _JSUint8Array {
+  external factory _JSUint8Array(JSNumber length);
+}
+
 Future<ByteBuffer> readVideoFramePixelsUnmodified(VideoFrame videoFrame) async {
   final int size = videoFrame.allocationSize().toInt();
-  final Uint8List destination = Uint8List(size);
+
+  // In dart2wasm, Uint8List is not the same as a JS Uint8Array. So we
+  // explicitly construct the JS object here.
+  final JSUint8Array destination = _JSUint8Array(size.toJS) as JSUint8Array;
   final JsPromise copyPromise = videoFrame.copyTo(destination);
   await promiseToFuture<void>(copyPromise);
-  return destination.buffer;
+
+  // In dart2wasm, `toDart` incurs a copy here. On JS backends, this is a
+  // no-op.
+  return destination.toDart.buffer;
 }
 
 Future<Uint8List> encodeVideoFrameAsPng(VideoFrame videoFrame) async {

engine/src/flutter/lib/web_ui/test/canvaskit/canvas_golden_test.dart

@@ -802,7 +802,7 @@ void testMain() {
 
     test('emoji text with skin tone', () async {
       await testSampleText('emoji_with_skin_tone', '👋🏿 👋🏾 👋🏽 👋🏼 👋🏻');
-    }, skip: isWasm || isSafari || isFirefox); // https://github.com/flutter/flutter/issues/124068
+    }, timeout: const Timeout.factor(2));
 
     // Make sure we clear the canvas in between frames.
     test('empty frame after contentful frame', () async {

engine/src/flutter/lib/web_ui/test/canvaskit/image_golden_test.dart

@@ -887,9 +887,7 @@ void _testCkBrowserImageDecoder() {
       expect(rgba!.buffer.asUint8List(), expectedColors[i]);
     }
     testCollector.collectNow();
-    // TODO(jacksongardner): enable on wasm
-    // see https://github.com/flutter/flutter/issues/118334
-  }, skip: isWasm);
+  });
 
   test('ImageDecoder expires after inactivity', () async {
     const Duration testExpireDuration = Duration(milliseconds: 100);
@@ -934,9 +932,7 @@ void _testCkBrowserImageDecoder() {
 
     testCollector.collectNow();
     debugRestoreWebDecoderExpireDuration();
-    // TODO(jacksongardner): enable on wasm
-    // see https://github.com/flutter/flutter/issues/118334
-  }, skip: isWasm);
+  });
 }
 
 Future<void> expectFrameData(ui.FrameInfo frame, List<int> data) async {

engine/src/flutter/lib/web_ui/test/engine/channel_buffers_test.dart

@@ -271,7 +271,7 @@ void testMain() {
       'b: seven',
       '-9',
     ]);
-  }, skip: isWasm); // https://github.com/dart-lang/sdk/issues/50778
+  });
 
   test('ChannelBuffers.clearListener', () async {
     final List<String> log = <String>[];
@@ -365,7 +365,7 @@ void testMain() {
       'callback1: true',
       'callback2: true',
     ]);
-  }, skip: isWasm); // https://github.com/dart-lang/sdk/issues/50778
+  });
 }
 
 class _TestChannelBuffers extends ui.ChannelBuffers {