Migrate web_validator to null safety (#80095)

packages/flutter_tools/lib/src/custom_devices/custom_devices_config.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:meta/meta.dart';
 
 import '../base/config.dart';
@@ -23,9 +21,9 @@ class CustomDevicesConfig {
   /// when it's not valid JSON (which other configurations do) and will not
   /// be implicitly created when it doesn't exist.
   CustomDevicesConfig({
-    @required FileSystem fileSystem,
-    @required Logger logger,
-    @required Platform platform
+    required FileSystem fileSystem,
+    required Logger logger,
+    required Platform platform
   }) : _fileSystem = fileSystem,
        _config = Config(
          _kCustomDevicesConfigName,
@@ -40,9 +38,9 @@ class CustomDevicesConfig {
 
   @visibleForTesting
   CustomDevicesConfig.test({
-    @required FileSystem fileSystem,
-    Directory directory,
-    @required Logger logger
+    required FileSystem fileSystem,
+    Directory? directory,
+    required Logger logger
   }) : _fileSystem = fileSystem,
        _config = Config.test(
          name: _kCustomDevicesConfigName,

packages/flutter_tools/lib/src/flutter_features.dart

@@ -2,10 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
-import 'package:meta/meta.dart';
-
 import 'base/config.dart';
 import 'base/platform.dart';
 import 'features.dart';
@@ -13,9 +9,9 @@ import 'version.dart';
 
 class FlutterFeatureFlags implements FeatureFlags {
   FlutterFeatureFlags({
-    @required FlutterVersion flutterVersion,
-    @required Config config,
-    @required Platform platform,
+    required FlutterVersion flutterVersion,
+    required Config config,
+    required Platform platform,
   }) : _flutterVersion = flutterVersion,
        _config = config,
        _platform = platform;
@@ -66,7 +62,7 @@ class FlutterFeatureFlags implements FeatureFlags {
     }
     bool isEnabled = featureSetting.enabledByDefault;
     if (feature.configSetting != null) {
-      final bool configOverride = _config.getValue(feature.configSetting) as bool;
+      final bool? configOverride = _config.getValue(feature.configSetting!) as bool?;
       if (configOverride != null) {
         isEnabled = configOverride;
       }

packages/flutter_tools/lib/src/ios/code_signing.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 'package:process/process.dart';
 
 import '../base/common.dart';

packages/flutter_tools/lib/src/web/web_validator.dart

@@ -2,10 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
-import 'package:meta/meta.dart';
-
 import '../base/platform.dart';
 import '../doctor_validator.dart';
 import 'chrome.dart';
@@ -52,8 +48,8 @@ abstract class ChromiumValidator extends DoctorValidator {
 /// A validator that checks whether Chrome is installed and can run.
 class ChromeValidator extends ChromiumValidator {
   const ChromeValidator({
-    @required Platform platform,
-    @required ChromiumLauncher chromiumLauncher,
+    required Platform platform,
+    required ChromiumLauncher chromiumLauncher,
   }) : _platform = platform,
        _chromiumLauncher = chromiumLauncher,
        super('Chrome - develop for the web');
@@ -71,8 +67,8 @@ class ChromeValidator extends ChromiumValidator {
 /// A validator that checks whether Edge is installed and can run.
 class EdgeValidator extends ChromiumValidator {
   const EdgeValidator({
-    @required Platform platform,
-    @required ChromiumLauncher chromiumLauncher,
+    required Platform platform,
+    required ChromiumLauncher chromiumLauncher,
   }) : _platform = platform,
        _chromiumLauncher = chromiumLauncher,
        super('Edge - develop for the web');

packages/flutter_tools/test/general.shard/web/web_validator_test.dart

@@ -2,11 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/base/os.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/doctor_validator.dart';
 import 'package:flutter_tools/src/web/chrome.dart';
@@ -16,11 +15,11 @@ import '../../src/common.dart';
 import '../../src/fake_process_manager.dart';
 
 void main() {
-  Platform platform;
-  FakeProcessManager fakeProcessManager;
-  ChromiumLauncher chromeLauncher;
-  FileSystem fileSystem;
-  ChromiumValidator webValidator;
+  late Platform platform;
+  late FakeProcessManager fakeProcessManager;
+  late ChromiumLauncher chromeLauncher;
+  late FileSystem fileSystem;
+  late ChromiumValidator webValidator;
 
   setUp(() {
     fileSystem = MemoryFileSystem.test();
@@ -33,7 +32,12 @@ void main() {
       fileSystem: fileSystem,
       platform: platform,
       processManager: fakeProcessManager,
-      operatingSystemUtils: null,
+      operatingSystemUtils: OperatingSystemUtils(
+        fileSystem: fileSystem,
+        logger: BufferLogger.test(),
+        platform: platform,
+        processManager: fakeProcessManager,
+      ),
       browserFinder: findChromeExecutable,
       logger: BufferLogger.test(),
     );