diff --git a/lib/web_ui/lib/initialization.dart b/lib/web_ui/lib/initialization.dart
index 13662b627b2a5..be7572cedcccc 100644
--- a/lib/web_ui/lib/initialization.dart
+++ b/lib/web_ui/lib/initialization.dart
@@ -95,3 +95,61 @@ set debugEmulateFlutterTesterEnvironment(bool value) {
 bool _debugEmulateFlutterTesterEnvironment = false;
 engine.AssetManager get webOnlyAssetManager => _assetManager!;
 engine.FontCollection get webOnlyFontCollection => _fontCollection!;
+
+/// Provides a compile time constant to customize flutter framework and other
+/// users of ui engine for web runtime.
+const bool isWeb = true;
+
+/// Web specific SMI. Used by bitfield. The 0x3FFFFFFFFFFFFFFF used on VM
+/// is not supported on Web platform.
+const int kMaxUnsignedSMI = -1;
+
+void webOnlyInitializeEngine() {
+  engine.initializeEngine();
+}
+
+void webOnlySetPluginHandler(Future<void> Function(String, ByteData?, PlatformMessageResponseCallback?) handler) {
+  engine.pluginMessageCallHandler = handler;
+}
+
+// TODO(yjbanov): The code below was temporarily moved from lib/web_ui/lib/src/engine/platform_views.dart
+//                during the NNBD migration so that `dart:ui` does not have to export `dart:_engine`. NNBD
+//                does not allow exported non-migrated libraries from migrated libraries. When `dart:_engine`
+//                is migrated, we can move it back.
+
+/// A function which takes a unique `id` and creates an HTML element.
+typedef PlatformViewFactory = html.Element Function(int viewId);
+
+/// A registry for factories that create platform views.
+class PlatformViewRegistry {
+  /// Register [viewTypeId] as being creating by the given [factory].
+  bool registerViewFactory(String viewTypeId, PlatformViewFactory viewFactory,
+      {bool isVisible = true}) {
+    // TODO(web): Deprecate this once there's another way of calling `registerFactory` (js interop?)
+    return engine.platformViewManager
+        .registerFactory(viewTypeId, viewFactory, isVisible: isVisible);
+  }
+}
+
+/// The platform view registry for this app.
+final PlatformViewRegistry platformViewRegistry = PlatformViewRegistry();
+
+// TODO(yjbanov): remove _Callback, _Callbacker, and _futurize. They are here only
+//                because the analyzer wasn't able to infer the correct types during
+//                NNBD migration.
+typedef _Callback<T> = void Function(T result);
+typedef _Callbacker<T> = String? Function(_Callback<T> callback);
+Future<T> _futurize<T>(_Callbacker<T> callbacker) {
+  final Completer<T> completer = Completer<T>.sync();
+  final String? error = callbacker((T t) {
+    if (t == null) {
+      completer.completeError(Exception('operation failed'));
+    } else {
+      completer.complete(t);
+    }
+  });
+  if (error != null) {
+    throw Exception(error);
+  }
+  return completer.future;
+}
diff --git a/lib/web_ui/lib/ui.dart b/lib/web_ui/lib/ui.dart
index e47bb5a2dc577..baa2a5c2b7a26 100644
--- a/lib/web_ui/lib/ui.dart
+++ b/lib/web_ui/lib/ui.dart
@@ -35,61 +35,3 @@ part 'semantics.dart';
 part 'text.dart';
 part 'tile_mode.dart';
 part 'window.dart';
-
-/// Provides a compile time constant to customize flutter framework and other
-/// users of ui engine for web runtime.
-const bool isWeb = true;
-
-/// Web specific SMI. Used by bitfield. The 0x3FFFFFFFFFFFFFFF used on VM
-/// is not supported on Web platform.
-const int kMaxUnsignedSMI = -1;
-
-void webOnlyInitializeEngine() {
-  engine.initializeEngine();
-}
-
-void webOnlySetPluginHandler(Future<void> Function(String, ByteData?, PlatformMessageResponseCallback?) handler) {
-  engine.pluginMessageCallHandler = handler;
-}
-
-// TODO(yjbanov): The code below was temporarily moved from lib/web_ui/lib/src/engine/platform_views.dart
-//                during the NNBD migration so that `dart:ui` does not have to export `dart:_engine`. NNBD
-//                does not allow exported non-migrated libraries from migrated libraries. When `dart:_engine`
-//                is migrated, we can move it back.
-
-/// A function which takes a unique `id` and creates an HTML element.
-typedef PlatformViewFactory = html.Element Function(int viewId);
-
-/// A registry for factories that create platform views.
-class PlatformViewRegistry {
-  /// Register [viewTypeId] as being creating by the given [factory].
-  bool registerViewFactory(String viewTypeId, PlatformViewFactory viewFactory,
-      {bool isVisible = true}) {
-    // TODO(web): Deprecate this once there's another way of calling `registerFactory` (js interop?)
-    return engine.platformViewManager
-        .registerFactory(viewTypeId, viewFactory, isVisible: isVisible);
-  }
-}
-
-/// The platform view registry for this app.
-final PlatformViewRegistry platformViewRegistry = PlatformViewRegistry();
-
-// TODO(yjbanov): remove _Callback, _Callbacker, and _futurize. They are here only
-//                because the analyzer wasn't able to infer the correct types during
-//                NNBD migration.
-typedef _Callback<T> = void Function(T result);
-typedef _Callbacker<T> = String? Function(_Callback<T> callback);
-Future<T> _futurize<T>(_Callbacker<T> callbacker) {
-  final Completer<T> completer = Completer<T>.sync();
-  final String? error = callbacker((T t) {
-    if (t == null) {
-      completer.completeError(Exception('operation failed'));
-    } else {
-      completer.complete(t);
-    }
-  });
-  if (error != null) {
-    throw Exception(error);
-  }
-  return completer.future;
-}