[web] Move webOnlyAssetManager to dart:ui_web (flutter/engine#42642)

Moving `webOnlyAssetManager` to `dart:ui_web` and renaming it to simply `assetManager`. This will make it easier for plugins and apps to get a hold of the asset manager without doing `dart:ui` shims or other shenanigans.

Part of https://github.com/flutter/flutter/issues/126831

engine/src/flutter/ci/licenses_golden/licenses_flutter

@@ -1893,7 +1893,6 @@ ORIGIN: ../../../flutter/lib/web_ui/lib/semantics.dart + ../../../flutter/LICENS
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/alarm_clock.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/app_bootstrap.dart + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/assets.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/browser_detection.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/canvas_pool.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/canvaskit/canvas.dart + ../../../flutter/LICENSE
@@ -2109,6 +2108,7 @@ ORIGIN: ../../../flutter/lib/web_ui/lib/text.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/tile_mode.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/ui.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web.dart + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web/asset_manager.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web/navigation/platform_location.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web/navigation/url_strategy.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web/platform_view_registry.dart + ../../../flutter/LICENSE
@@ -4572,7 +4572,6 @@ FILE: ../../../flutter/lib/web_ui/lib/semantics.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/alarm_clock.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/app_bootstrap.dart
-FILE: ../../../flutter/lib/web_ui/lib/src/engine/assets.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/browser_detection.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/canvas_pool.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/canvaskit/canvas.dart
@@ -4788,6 +4787,7 @@ FILE: ../../../flutter/lib/web_ui/lib/text.dart
 FILE: ../../../flutter/lib/web_ui/lib/tile_mode.dart
 FILE: ../../../flutter/lib/web_ui/lib/ui.dart
 FILE: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web.dart
+FILE: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web/asset_manager.dart
 FILE: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web/navigation/platform_location.dart
 FILE: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web/navigation/url_strategy.dart
 FILE: ../../../flutter/lib/web_ui/lib/ui_web/src/ui_web/platform_view_registry.dart

engine/src/flutter/lib/web_ui/lib/initialization.dart

@@ -111,11 +111,18 @@ set debugEmulateFlutterTesterEnvironment(bool value) {
 bool _debugEmulateFlutterTesterEnvironment = false;
 
 /// Provides the asset manager.
-// TODO(yjbanov): this function should not return a private type. Instead, we
-//                should create a public interface for the returned value that's
-//                implemented by the engine.
-//                https://github.com/flutter/flutter/issues/100394
-engine.AssetManager get webOnlyAssetManager => engine.assetManager;
+// TODO(mdebbar): Deprecate this and remove it.
+// https://github.com/flutter/flutter/issues/127395
+ui_web.AssetManager get webOnlyAssetManager {
+  assert(() {
+    engine.printWarning(
+      'The webOnlyAssetManager getter is deprecated and will be removed in a '
+      'future release. Please use `assetManager` from `dart:ui_web` instead.',
+    );
+    return true;
+  }());
+  return ui_web.assetManager;
+}
 
 /// Sets the handler that forwards platform messages to web plugins.
 ///

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

@@ -17,7 +17,6 @@ library engine;
 
 export 'engine/alarm_clock.dart';
 export 'engine/app_bootstrap.dart';
-export 'engine/assets.dart';
 export 'engine/browser_detection.dart';
 export 'engine/canvas_pool.dart';
 export 'engine/canvaskit/canvas.dart';

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

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:typed_data';
 
 import 'package:ui/src/engine.dart';
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 // This URL was found by using the Google Fonts Developer API to find the URL
 // for Roboto. The API warns that this URL is not stable. In order to update
@@ -109,7 +110,7 @@ class SkiaFontCollection implements FlutterFontCollection {
         loadedRoboto = true;
       }
       for (final FontAsset fontAsset in family.fontAssets) {
-        final String url = assetManager.getAssetUrl(fontAsset.asset);
+        final String url = ui_web.assetManager.getAssetUrl(fontAsset.asset);
         pendingDownloads.add(_downloadFont(fontAsset.asset, url, family.name));
       }
     }

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

@@ -8,6 +8,7 @@ import 'dart:typed_data';
 
 import 'package:ui/src/engine.dart';
 import 'package:ui/ui.dart' as ui;
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 enum CanvasKitVariant {
   /// The appropriate variant is chosen based on the browser.
@@ -384,7 +385,7 @@ class CanvasKitRenderer implements Renderer {
     if (_programs.containsKey(assetKey)) {
       return _programs[assetKey]!;
     }
-    return _programs[assetKey] = assetManager.load(assetKey).then((ByteData data) {
+    return _programs[assetKey] = ui_web.assetManager.load(assetKey).then((ByteData data) {
       return CkFragmentProgram.fromBytes(assetKey, data.buffer.asUint8List());
     });
   }

engine/src/flutter/lib/web_ui/lib/src/engine/fonts.dart

@@ -8,6 +8,7 @@ import 'dart:js_interop';
 import 'dart:typed_data';
 
 import 'package:ui/src/engine.dart';
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 class FontAsset {
   FontAsset(this.asset, this.descriptors);
@@ -29,8 +30,8 @@ class FontManifest {
   final List<FontFamily> families;
 }
 
-Future<FontManifest> fetchFontManifest(AssetManager assetManager) async {
-  final HttpFetchResponse response = await assetManager.loadAsset('FontManifest.json');
+Future<FontManifest> fetchFontManifest(ui_web.AssetManager assetManager) async {
+  final HttpFetchResponse response = await assetManager.loadAsset('FontManifest.json') as HttpFetchResponse;
   if (!response.hasPayload) {
     printWarning('Font manifest does not exist at `${response.url}` - ignoring.');
     return FontManifest(<FontFamily>[]);

engine/src/flutter/lib/web_ui/lib/src/engine/initialization.dart

@@ -8,6 +8,7 @@ import 'dart:js_interop';
 
 import 'package:ui/src/engine.dart';
 import 'package:ui/ui.dart' as ui;
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 import 'package:web_test_fonts/web_test_fonts.dart';
 
 /// The mode the app is running in.
@@ -56,7 +57,7 @@ void debugEmulateHotRestart() {
 
 /// Fully initializes the engine, including services and UI.
 Future<void> initializeEngine({
-  AssetManager? assetManager,
+  ui_web.AssetManager? assetManager,
 }) async {
   await initializeEngineServices(assetManager: assetManager);
   await initializeEngineUi();
@@ -114,7 +115,7 @@ void debugResetEngineInitializationState() {
 ///  * [initializeEngineUi], which is typically called after this function, and
 ///    puts UI elements on the page.
 Future<void> initializeEngineServices({
-  AssetManager? assetManager,
+  ui_web.AssetManager? assetManager,
   JsFlutterConfiguration? jsConfiguration
 }) async {
   if (_initializationState != DebugEngineInitializationState.uninitialized) {
@@ -193,7 +194,7 @@ Future<void> initializeEngineServices({
     }
   };
 
-  assetManager ??= AssetManager(assetBase: configuration.assetBase);
+  assetManager ??= ui_web.AssetManager(assetBase: configuration.assetBase);
   _setAssetManager(assetManager);
 
   Future<void> initializeRendererCallback () async => renderer.initialize();
@@ -229,10 +230,10 @@ Future<void> initializeEngineUi() async {
   _initializationState = DebugEngineInitializationState.initialized;
 }
 
-AssetManager get assetManager => _assetManager!;
-AssetManager? _assetManager;
+ui_web.AssetManager get engineAssetManager => _assetManager!;
+ui_web.AssetManager? _assetManager;
 
-void _setAssetManager(AssetManager assetManager) {
+void _setAssetManager(ui_web.AssetManager assetManager) {
   if (assetManager == _assetManager) {
     return;
   }
@@ -253,7 +254,7 @@ Future<void> _downloadAssetFonts() async {
   }
 
   if (_assetManager != null) {
-    await renderer.fontCollection.loadAssetFonts(await fetchFontManifest(assetManager));
+    await renderer.fontCollection.loadAssetFonts(await fetchFontManifest(ui_web.assetManager));
   }
 }
 

engine/src/flutter/lib/web_ui/lib/src/engine/platform_dispatcher.dart

@@ -7,22 +7,10 @@ import 'dart:convert';
 import 'dart:js_interop';
 import 'dart:typed_data';
 
-import 'package:ui/src/engine/canvaskit/renderer.dart';
-import 'package:ui/src/engine/renderer.dart';
 import 'package:ui/ui.dart' as ui;
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
-import '../engine.dart'  show flutterViewEmbedder, platformViewManager, registerHotRestartListener;
-import 'clipboard.dart';
-import 'dom.dart';
-import 'mouse_cursor.dart';
-import 'platform_views/message_handler.dart';
-import 'plugins.dart';
-import 'safe_browser_api.dart';
-import 'semantics.dart';
-import 'services.dart';
-import 'text_editing/text_editing.dart';
-import 'util.dart';
-import 'window.dart';
+import '../engine.dart';
 
 /// Requests that the browser schedule a frame.
 ///
@@ -688,7 +676,7 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
 
   Future<void> _handleFlutterAssetsMessage(String url, ui.PlatformMessageResponseCallback? callback) async {
     try {
-      final HttpFetchResponse response = await ui.webOnlyAssetManager.loadAsset(url);
+      final HttpFetchResponse response = await ui_web.assetManager.loadAsset(url) as HttpFetchResponse;
       final ByteBuffer assetData = await response.asByteBuffer();
       replyToPlatformMessage(callback, assetData.asByteData());
     } catch (error) {

engine/src/flutter/lib/web_ui/lib/src/engine/skwasm/skwasm_impl/font_collection.dart

@@ -10,6 +10,7 @@ import 'dart:typed_data';
 
 import 'package:ui/src/engine.dart';
 import 'package:ui/src/engine/skwasm/skwasm_impl.dart';
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 // This URL was found by using the Google Fonts Developer API to find the URL
 // for Roboto. The API warns that this URL is not stable. In order to update
@@ -99,12 +100,12 @@ class SkwasmFontCollection implements FlutterFontCollection {
   Future<FontLoadError?> _downloadFontAsset(FontAsset asset, String family) async {
     final HttpFetchResponse response;
     try {
-      response = await assetManager.loadAsset(asset.asset);
+      response = await ui_web.assetManager.loadAsset(asset.asset) as HttpFetchResponse;
     } catch (error) {
-      return FontDownloadError(assetManager.getAssetUrl(asset.asset), error);
+      return FontDownloadError(ui_web.assetManager.getAssetUrl(asset.asset), error);
     }
     if (!response.hasPayload) {
-      return FontNotFoundError(assetManager.getAssetUrl(asset.asset));
+      return FontNotFoundError(ui_web.assetManager.getAssetUrl(asset.asset));
     }
     int length = 0;
     final List<JSUint8Array> chunks = <JSUint8Array>[];
@@ -128,7 +129,7 @@ class SkwasmFontCollection implements FlutterFontCollection {
       skStringFree(familyNameHandle);
       return null;
     } else {
-      return FontInvalidDataError(assetManager.getAssetUrl(asset.asset));
+      return FontInvalidDataError(ui_web.assetManager.getAssetUrl(asset.asset));
     }
   }
 

engine/src/flutter/lib/web_ui/lib/src/engine/skwasm/skwasm_impl/renderer.dart

@@ -10,6 +10,7 @@ import 'dart:typed_data';
 import 'package:ui/src/engine.dart';
 import 'package:ui/src/engine/skwasm/skwasm_impl.dart';
 import 'package:ui/ui.dart' as ui;
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 class SkwasmRenderer implements Renderer {
   late DomCanvasElement sceneElement;
@@ -438,7 +439,7 @@ class SkwasmRenderer implements Renderer {
     if (_programs.containsKey(assetKey)) {
       return _programs[assetKey]!;
     }
-    return _programs[assetKey] = assetManager.load(assetKey).then((ByteData data) {
+    return _programs[assetKey] = ui_web.assetManager.load(assetKey).then((ByteData data) {
       return SkwasmFragmentProgram.fromBytes(assetKey, data.buffer.asUint8List());
     });
   }

engine/src/flutter/lib/web_ui/lib/src/engine/skwasm/skwasm_stub/renderer.dart

@@ -8,6 +8,7 @@ import 'dart:typed_data';
 
 import 'package:ui/src/engine.dart';
 import 'package:ui/ui.dart' as ui;
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 class SkwasmRenderer implements Renderer {
   @override
@@ -171,7 +172,7 @@ class SkwasmRenderer implements Renderer {
     if (_programs.containsKey(assetKey)) {
       return _programs[assetKey]!;
     }
-    return _programs[assetKey] = assetManager.load(assetKey).then((ByteData data) {
+    return _programs[assetKey] = ui_web.assetManager.load(assetKey).then((ByteData data) {
       return CkFragmentProgram.fromBytes(assetKey, data.buffer.asUint8List());
     });
   }

engine/src/flutter/lib/web_ui/lib/src/engine/text/font_collection.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:typed_data';
 
 import 'package:ui/src/engine.dart';
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 /// This class is responsible for registering and loading fonts.
 ///
@@ -14,7 +15,7 @@ import 'package:ui/src/engine.dart';
 /// font manifest. If test fonts are enabled, then call
 /// [debugDownloadTestFonts] as well.
 class HtmlFontCollection implements FlutterFontCollection {
-  /// Reads the font manifest using the [assetManager] and downloads all of the
+  /// Reads the font manifest using the [ui_web.assetManager] and downloads all of the
   /// fonts declared within.
   @override
   Future<AssetFontsResult> loadAssetFonts(FontManifest manifest) async {
@@ -149,7 +150,7 @@ class HtmlFontCollection implements FlutterFontCollection {
   ) async {
     // try/catch because `new FontFace` can crash with an improper font family.
     try {
-      final DomFontFace fontFace = createDomFontFace(family, 'url(${assetManager.getAssetUrl(asset)})', descriptors);
+      final DomFontFace fontFace = createDomFontFace(family, 'url(${ui_web.assetManager.getAssetUrl(asset)})', descriptors);
       return await fontFace.load();
     } catch (e) {
       printWarning('Error while loading font family "$family":\n$e');

engine/src/flutter/lib/web_ui/lib/ui_web/src/ui_web.dart

@@ -8,6 +8,7 @@
 // ignore: unnecessary_library_directive
 library ui_web;
 
+export 'ui_web/asset_manager.dart';
 export 'ui_web/navigation/platform_location.dart';
 export 'ui_web/navigation/url_strategy.dart';
 export 'ui_web/platform_view_registry.dart';

engine/src/flutter/lib/web_ui/lib/ui_web/src/ui_web/asset_manager.dart

@@ -5,8 +5,10 @@
 import 'dart:convert';
 import 'dart:typed_data';
 
-import 'dom.dart';
-import 'util.dart';
+import 'package:ui/src/engine.dart';
+
+/// Provides the [AssetManager] used by the Flutter Engine.
+AssetManager get assetManager => engineAssetManager;
 
 /// This class downloads assets over the network.
 ///
@@ -79,11 +81,11 @@ class AssetManager {
   }
 
   /// Loads an asset and returns the server response.
-  Future<HttpFetchResponse> loadAsset(String asset) {
+  Future<Object> loadAsset(String asset) {
     return httpFetch(getAssetUrl(asset));
   }
 
-  /// Loads an asset using an [DomXMLHttpRequest] and returns data as [ByteData].
+  /// Loads an asset using an [XMLHttpRequest] and returns data as [ByteData].
   Future<ByteData> load(String asset) async {
     final String url = getAssetUrl(asset);
     final HttpFetchResponse response = await httpFetch(url);

engine/src/flutter/lib/web_ui/test/common/fake_asset_manager.dart

@@ -6,8 +6,9 @@ import 'dart:convert';
 import 'dart:typed_data';
 
 import 'package:ui/src/engine.dart';
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
-class FakeAssetManager implements AssetManager {
+class FakeAssetManager implements ui_web.AssetManager {
   FakeAssetManager();
 
   @override

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

@@ -8,6 +8,7 @@ library;
 import 'package:test/bootstrap/browser.dart';
 import 'package:test/test.dart';
 import 'package:ui/src/engine.dart';
+import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 import '../common/matchers.dart';
 
@@ -23,7 +24,7 @@ void testMain() {
     });
 
     test('initializes with default values', () {
-      final AssetManager assets = AssetManager();
+      final ui_web.AssetManager assets = ui_web.AssetManager();
 
       expect(
         assets.getAssetUrl('asset.txt'),
@@ -33,25 +34,25 @@ void testMain() {
     });
 
     test('assetsDir changes the directory where assets are stored', () {
-      final AssetManager assets = AssetManager(assetsDir: 'static');
+      final ui_web.AssetManager assets = ui_web.AssetManager(assetsDir: 'static');
 
       expect(assets.getAssetUrl('asset.txt'), 'static/asset.txt');
     });
 
     test('assetBase must end with slash', () {
       expect(() {
-        AssetManager(assetBase: '/deployment');
+        ui_web.AssetManager(assetBase: '/deployment');
       }, throwsAssertionError);
     });
 
     test('assetBase can be relative', () {
-      final AssetManager assets = AssetManager(assetBase: 'base/');
+      final ui_web.AssetManager assets = ui_web.AssetManager(assetBase: 'base/');
 
       expect(assets.getAssetUrl('asset.txt'), 'base/assets/asset.txt');
     });
 
     test('assetBase can be absolute', () {
-      final AssetManager assets = AssetManager(
+      final ui_web.AssetManager assets = ui_web.AssetManager(
         assetBase: 'https://www.gstatic.com/my-app/',
       );
 
@@ -62,7 +63,7 @@ void testMain() {
     });
 
     test('assetBase in conjunction with assetsDir, fully custom paths', () {
-      final AssetManager assets = AssetManager(
+      final ui_web.AssetManager assets = ui_web.AssetManager(
         assetBase: '/asset/base/',
         assetsDir: 'static',
       );
@@ -71,7 +72,7 @@ void testMain() {
     });
 
     test('Fully-qualified asset URLs are untouched', () {
-      final AssetManager assets = AssetManager();
+      final ui_web.AssetManager assets = ui_web.AssetManager();
 
       expect(
         assets.getAssetUrl('https://static.my-app.com/favicon.ico'),
@@ -80,7 +81,7 @@ void testMain() {
     });
 
     test('Fully-qualified asset URLs are untouched (even with assetBase)', () {
-      final AssetManager assets = AssetManager(
+      final ui_web.AssetManager assets = ui_web.AssetManager(
         assetBase: 'https://static.my-app.com/',
       );
 
@@ -98,20 +99,20 @@ void testMain() {
     });
 
     test('reads value from DOM', () {
-      final AssetManager assets = AssetManager();
+      final ui_web.AssetManager assets = ui_web.AssetManager();
 
       expect(assets.getAssetUrl('asset.txt'), '/dom/base/assets/asset.txt');
     });
 
     test('reads value from DOM (only once!)', () {
-      final AssetManager firstManager = AssetManager();
+      final ui_web.AssetManager firstManager = ui_web.AssetManager();
       expect(
         firstManager.getAssetUrl('asset.txt'),
         '/dom/base/assets/asset.txt',
       );
 
       removeAssetBaseMeta();
-      final AssetManager anotherManager = AssetManager();
+      final ui_web.AssetManager anotherManager = ui_web.AssetManager();
 
       expect(
         firstManager.getAssetUrl('asset.txt'),