Fix is canvas kit bool (#116944)

* isCanvasKit implement and test

* isCanvasKit implement and test

* ++

* forgot license

* make isCanvasKit a getter

* addressed comments

* forgot to change names of integration test files

* typo

* simplified tests

* comments

dev/bots/test.dart

@@ -1177,6 +1177,11 @@ Future<void> _runWebLongRunningTests() async {
     () => _runWebE2eTest('url_strategy_integration', buildMode: 'profile', renderer: 'canvaskit'),
     () => _runWebE2eTest('url_strategy_integration', buildMode: 'release', renderer: 'html'),
 
+    // This test doesn't do anything interesting w.r.t. rendering, so we don't run the full build mode x renderer matrix.
+    () => _runWebE2eTest('capabilities_integration_canvaskit', buildMode: 'debug', renderer: 'auto'),
+    () => _runWebE2eTest('capabilities_integration_canvaskit', buildMode: 'profile', renderer: 'canvaskit'),
+    () => _runWebE2eTest('capabilities_integration_html', buildMode: 'release', renderer: 'html'),
+
     () => _runWebTreeshakeTest(),
 
     () => _runFlutterDriverWebTest(

dev/integration_tests/web_e2e_tests/test_driver/capabilities_integration_canvaskit.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 'package:flutter/foundation.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:integration_test/integration_test.dart';
+
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  testWidgets('isCanvasKit returns true in CanvasKit mode', (WidgetTester tester) async {
+    await tester.pumpAndSettle();
+    expect(isCanvasKit, true);
+  });
+}

dev/integration_tests/web_e2e_tests/test_driver/capabilities_integration_canvaskit_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 'package:integration_test/integration_test_driver.dart' as test;
+
+Future<void> main() async => test.integrationDriver();

dev/integration_tests/web_e2e_tests/test_driver/capabilities_integration_html.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 'package:flutter/foundation.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:integration_test/integration_test.dart';
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  testWidgets('isCanvasKit returns false in HTML mode', (WidgetTester tester) async {
+    await tester.pumpAndSettle();
+    expect(isCanvasKit, false);
+  });
+}

dev/integration_tests/web_e2e_tests/test_driver/capabilities_integration_html_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 'package:integration_test/integration_test_driver.dart' as test;
+
+Future<void> main() async => test.integrationDriver();

packages/flutter/lib/foundation.dart

@@ -24,6 +24,7 @@ export 'src/foundation/assertions.dart';
 export 'src/foundation/basic_types.dart';
 export 'src/foundation/binding.dart';
 export 'src/foundation/bitfield.dart';
+export 'src/foundation/capabilities.dart';
 export 'src/foundation/change_notifier.dart';
 export 'src/foundation/collections.dart';
 export 'src/foundation/consolidate_response.dart';

packages/flutter/lib/src/foundation/_capabilities_io.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.
+
+/// The dart:io implementation of [isCanvasKit].
+///
+/// This bool shouldn't be used outside of web.
+bool get isCanvasKit {
+  throw UnimplementedError('isCanvasKit is not implemented for dart:io.');
+}

packages/flutter/lib/src/foundation/_capabilities_web.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 'package:js/js.dart';
+
+// This value is set by the engine. It is used to determine if the application is
+// using canvaskit.
+@JS('window.flutterCanvasKit')
+external Object? get _windowFlutterCanvasKit;
+
+/// The web implementation of [isCanvasKit]
+bool get isCanvasKit => _windowFlutterCanvasKit != null;

packages/flutter/lib/src/foundation/capabilities.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 '_capabilities_io.dart'
+  if (dart.library.js_util) '_capabilities_web.dart' as capabilities;
+
+/// Returns true if the application is using CanvasKit.
+///
+/// Only to be used for web.
+bool get isCanvasKit => capabilities.isCanvasKit;

packages/flutter/lib/src/foundation/constants.dart

@@ -69,6 +69,3 @@ const double precisionErrorTolerance = 1e-10;
 
 /// A constant that is true if the application was compiled to run on the web.
 const bool kIsWeb = bool.fromEnvironment('dart.library.js_util');
-
-/// A constant that is true if the application is using canvasKit
-const bool isCanvasKit = bool.fromEnvironment('FLUTTER_WEB_USE_SKIA');