[web] Cleanup everything HTML from the flutter tool and test harness

packages/flutter_test/lib/src/_matchers_web.dart

@@ -59,69 +59,37 @@ class MatchesGoldenFile extends AsyncMatcher {
       return 'matched too many widgets';
     }
     final Element element = elements.single;
-    final RenderObject renderObject = _findRepaintBoundary(element);
-    final Size size = renderObject.paintBounds.size;
-    final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.instance;
-    final ui.FlutterView view = binding.platformDispatcher.implicitView!;
-    final RenderView renderView = binding.renderViews.firstWhere(
-      (RenderView r) => r.flutterView == view,
-    );
 
-    if (isSkiaWeb) {
-      // In CanvasKit and Skwasm, use Layer.toImage to generate the screenshot.
-      final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.instance;
-      return binding.runAsync<String?>(() async {
-        assert(element.renderObject != null);
-        RenderObject renderObject = element.renderObject!;
-        while (!renderObject.isRepaintBoundary) {
-          renderObject = renderObject.parent!;
-        }
-        assert(!renderObject.debugNeedsPaint);
-        final OffsetLayer layer = renderObject.debugLayer! as OffsetLayer;
-        final ui.Image image = await layer.toImage(renderObject.paintBounds);
-        try {
-          final ByteData? bytes = await image.toByteData(format: ui.ImageByteFormat.png);
-          if (bytes == null) {
-            return 'could not encode screenshot.';
-          }
-          if (autoUpdateGoldenFiles) {
-            await goldenFileComparator.update(key, bytes.buffer.asUint8List());
-            return null;
-          }
-          try {
-            final bool success = await goldenFileComparator.compare(
-              bytes.buffer.asUint8List(),
-              key,
-            );
-            return success ? null : 'does not match';
-          } on TestFailure catch (ex) {
-            return ex.message;
-          }
-        } finally {
-          image.dispose();
+    // In CanvasKit and Skwasm, use Layer.toImage to generate the screenshot.
+    final TestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.instance;
+    return binding.runAsync<String?>(() async {
+      assert(element.renderObject != null);
+      RenderObject renderObject = element.renderObject!;
+      while (!renderObject.isRepaintBoundary) {
+        renderObject = renderObject.parent!;
+      }
+      assert(!renderObject.debugNeedsPaint);
+      final OffsetLayer layer = renderObject.debugLayer! as OffsetLayer;
+      final ui.Image image = await layer.toImage(renderObject.paintBounds);
+      try {
+        final ByteData? bytes = await image.toByteData(format: ui.ImageByteFormat.png);
+        if (bytes == null) {
+          return 'could not encode screenshot.';
         }
-      });
-    } else {
-      // In the HTML renderer, we don't have the ability to render an element
-      // to an image directly. Instead, we will use `window.render()` to render
-      // only the element being requested, and send a request to the test server
-      // requesting it to take a screenshot through the browser's debug interface.
-      _renderElement(view, renderObject);
-      final String? result = await binding.runAsync<String?>(() async {
         if (autoUpdateGoldenFiles) {
-          await webGoldenComparator.update(size.width, size.height, key);
+          await goldenFileComparator.update(key, bytes.buffer.asUint8List());
           return null;
         }
         try {
-          final bool success = await webGoldenComparator.compare(size.width, size.height, key);
+          final bool success = await goldenFileComparator.compare(bytes.buffer.asUint8List(), key);
           return success ? null : 'does not match';
         } on TestFailure catch (ex) {
           return ex.message;
         }
-      });
-      _renderElement(view, renderView);
-      return result;
-    }
+      } finally {
+        image.dispose();
+      }
+    });
   }
 
   @override
@@ -130,27 +98,3 @@ class MatchesGoldenFile extends AsyncMatcher {
     return description.add('one widget whose rasterized image matches golden image "$testNameUri"');
   }
 }
-
-RenderObject _findRepaintBoundary(Element element) {
-  assert(element.renderObject != null);
-  RenderObject renderObject = element.renderObject!;
-  while (!renderObject.isRepaintBoundary) {
-    renderObject = renderObject.parent!;
-  }
-  return renderObject;
-}
-
-void _renderElement(ui.FlutterView window, RenderObject renderObject) {
-  assert(renderObject.debugLayer != null);
-  final Layer layer = renderObject.debugLayer!;
-  final ui.SceneBuilder sceneBuilder = ui.SceneBuilder();
-  if (layer is OffsetLayer) {
-    sceneBuilder.pushOffset(-layer.offset.dx, -layer.offset.dy);
-  }
-  // ignore: invalid_use_of_visible_for_testing_member, invalid_use_of_protected_member
-  layer.updateSubtreeNeedsAddToScene();
-  // ignore: invalid_use_of_protected_member
-  layer.addToScene(sceneBuilder);
-  sceneBuilder.pop();
-  window.render(sceneBuilder.build());
-}