[web] Delete unused futurize util (flutter#177861)

Author: mdebbar

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

@@ -596,21 +596,14 @@ enum PixelFormat { rgba8888, bgra8888, rgbaFloat32 }
 typedef ImageDecoderCallback = void Function(Image result);
 
 abstract class FrameInfo {
-  FrameInfo._();
-  Duration get duration => Duration(milliseconds: _durationMillis);
-  int get _durationMillis => 0;
+  Duration get duration;
   Image get image;
 }
 
-class Codec {
-  Codec._();
-  int get frameCount => 0;
-  int get repetitionCount => 0;
-  Future<FrameInfo> getNextFrame() {
-    return engine.futurize<FrameInfo>(_getNextFrame);
-  }
-
-  String? _getNextFrame(engine.Callback<FrameInfo> callback) => null;
+abstract class Codec {
+  int get frameCount;
+  int get repetitionCount;
+  Future<FrameInfo> getNextFrame();
   void dispose() {}
 }
 

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

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:math' as math;
@@ -15,61 +14,6 @@ import 'browser_detection.dart' show isIOS15, isMacOrIOS;
 import 'dom.dart';
 import 'vector_math.dart';
 
-/// Generic callback signature, used by [futurize].
-typedef Callback<T> = void Function(T result);
-
-/// Signature for a method that receives a [Callback].
-///
-/// Return value should be null on success, and a string error message on
-/// failure.
-typedef Callbacker<T> = String? Function(Callback<T> callback);
-
-/// Converts a method that receives a value-returning callback to a method that
-/// returns a Future.
-///
-/// Return a [String] to cause an [Exception] to be synchronously thrown with
-/// that string as a message.
-///
-/// If the callback is called with null, the future completes with an error.
-///
-/// Example usage:
-///
-/// ```dart
-/// typedef IntCallback = void Function(int result);
-///
-/// String _doSomethingAndCallback(IntCallback callback) {
-///   Timer(const Duration(seconds: 1), () { callback(1); });
-/// }
-///
-/// Future<int> doSomething() {
-///   return futurize(_doSomethingAndCallback);
-/// }
-/// ```
-// Keep this in sync with _futurize in lib/ui/fixtures/ui_test.dart.
-Future<T> futurize<T>(Callbacker<T> callbacker) {
-  final Completer<T> completer = Completer<T>.sync();
-  // If the callback synchronously throws an error, then synchronously
-  // rethrow that error instead of adding it to the completer. This
-  // prevents the Zone from receiving an uncaught exception.
-  bool isSync = true;
-  final String? error = callbacker((T? t) {
-    if (t == null) {
-      if (isSync) {
-        throw Exception('operation failed');
-      } else {
-        completer.completeError(Exception('operation failed'));
-      }
-    } else {
-      completer.complete(t);
-    }
-  });
-  isSync = false;
-  if (error != null) {
-    throw Exception(error);
-  }
-  return completer.future;
-}
-
 /// Converts [matrix] to CSS transform value.
 String matrix4ToCssTransform(Matrix4 matrix) {
   return float64ListToCssTransform(matrix.storage);

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

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:typed_data';
 
 import 'package:test/bootstrap/browser.dart';
@@ -106,55 +105,6 @@ void testMain() {
     expect(element.style.color, '');
   });
 
-  test('futurize turns a Callbacker into a Future', () async {
-    final Future<String> stringFuture = futurize((Callback<String> callback) {
-      scheduleMicrotask(() {
-        callback('hello');
-      });
-      return null;
-    });
-    expect(await stringFuture, 'hello');
-  });
-
-  test('futurize converts error string to exception', () async {
-    try {
-      await futurize((Callback<String> callback) {
-        return 'this is an error';
-      });
-      fail('Expected it to throw');
-    } on Exception catch (exception) {
-      expect('$exception', contains('this is an error'));
-    }
-  });
-
-  test('futurize converts async null into an async operation failure', () async {
-    final Future<String?> stringFuture = futurize((Callback<String?> callback) {
-      scheduleMicrotask(() {
-        callback(null);
-      });
-      return null;
-    });
-
-    try {
-      await stringFuture;
-      fail('Expected it to throw');
-    } on Exception catch (exception) {
-      expect('$exception', contains('operation failed'));
-    }
-  });
-
-  test('futurize converts sync null into a sync operation failure', () async {
-    try {
-      await futurize((Callback<String?> callback) {
-        callback(null);
-        return null;
-      });
-      fail('Expected it to throw');
-    } on Exception catch (exception) {
-      expect('$exception', contains('operation failed'));
-    }
-  });
-
   test('unordered list equality', () {
     expect(unorderedListEqual<int>(null, null), isTrue);
     expect(unorderedListEqual<int>(<int>[], null), isTrue);