Use scheduleTask for adding licenses (#54493)

packages/flutter/lib/src/services/binding.dart

@@ -89,12 +89,7 @@ mixin ServicesBinding on BindingBase, SchedulerBinding {
   }
 
   Stream<LicenseEntry> _addLicenses() async* {
-    // We use timers here (rather than scheduleTask from the scheduler binding)
-    // because the services layer can't use the scheduler binding (the scheduler
-    // binding uses the services layer to manage its lifecycle events). Timers
-    // are what scheduleTask uses under the hood anyway. The only difference is
-    // that these will just run next, instead of being prioritized relative to
-    // the other tasks that might be running. Using _something_ here to break
+    // Using _something_ here to break
     // this into two parts is important because isolates take a while to copy
     // data at the moment, and if we receive the data in the same event loop
     // iteration as we send the data to the next isolate, we are definitely
@@ -105,14 +100,14 @@ mixin ServicesBinding on BindingBase, SchedulerBinding {
     //      https://github.com/dart-lang/sdk/issues/31960
     // TODO(ianh): Remove this complexity once these bugs are fixed.
     final Completer<String> rawLicenses = Completer<String>();
-    Timer.run(() async {
+    scheduleTask(() async {
       rawLicenses.complete(rootBundle.loadString('LICENSE', cache: false));
-    });
+    }, Priority.animation);
     await rawLicenses.future;
     final Completer<List<LicenseEntry>> parsedLicenses = Completer<List<LicenseEntry>>();
-    Timer.run(() async {
+    scheduleTask(() async {
       parsedLicenses.complete(compute(_parseLicenses, await rawLicenses.future, debugLabel: 'parseLicenses'));
-    });
+    }, Priority.animation);
     await parsedLicenses.future;
     yield* Stream<LicenseEntry>.fromIterable(await parsedLicenses.future);
   }

packages/flutter/test/services/binding_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:typed_data';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/scheduler.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter/src/services/binding.dart';
+
+import 'package:flutter_test/flutter_test.dart';
+
+const String license1 = '''
+L1Package1
+L1Package2
+L1Package3
+
+L1Paragraph1
+
+L1Paragraph2
+
+L1Paragraph3''';
+
+const String license2 = '''
+L2Package1
+L2Package2
+L2Package3
+
+L2Paragraph1
+
+L2Paragraph2
+
+L2Paragraph3''';
+
+const String licenses = '''
+$license1
+--------------------------------------------------------------------------------
+$license2
+''';
+
+class TestBinding extends BindingBase with SchedulerBinding, ServicesBinding {
+  @override
+  BinaryMessenger createBinaryMessenger() {
+    return super.createBinaryMessenger()
+      ..setMockMessageHandler('flutter/assets', (ByteData message) async {
+        if (const StringCodec().decodeMessage(message) == 'LICENSE') {
+          return const StringCodec().encodeMessage(licenses);
+        }
+        return null;
+      });
+  }
+}
+
+void main() {
+  test('Adds rootBundle LICENSES to LicenseRegistry', () async {
+    TestBinding(); // The test binding registers a mock handler that returns licenses for the LICENSE key
+
+    final List<LicenseEntry> licenses = await LicenseRegistry.licenses.toList();
+
+    expect(licenses[0].packages, equals(<String>['L1Package1', 'L1Package2', 'L1Package3']));
+    expect(licenses[0].paragraphs.map((LicenseParagraph p) => p.text),
+        equals(<String>['L1Paragraph1', 'L1Paragraph2', 'L1Paragraph3']));
+
+    expect(licenses[1].packages, equals(<String>['L2Package1', 'L2Package2', 'L2Package3']));
+    expect(licenses[1].paragraphs.map((LicenseParagraph p) => p.text),
+        equals(<String>['L2Paragraph1', 'L2Paragraph2', 'L2Paragraph3']));
+  });
+}