diff --git a/packages/flutter_tools/lib/src/android/deferred_components_gen_snapshot_validator.dart b/packages/flutter_tools/lib/src/android/deferred_components_gen_snapshot_validator.dart
index a4b8bbfa6d..e3c755e96a 100644
--- a/packages/flutter_tools/lib/src/android/deferred_components_gen_snapshot_validator.dart
+++ b/packages/flutter_tools/lib/src/android/deferred_components_gen_snapshot_validator.dart
@@ -33,7 +33,7 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
   DeferredComponentsGenSnapshotValidator(this.env, {
     bool exitOnFail = true,
     String title,
-  }) : super(env.projectDir, env.logger, exitOnFail: exitOnFail, title: title);
+  }) : super(env.projectDir, env.logger, env.platform, exitOnFail: exitOnFail, title: title);
 
   /// The build environment that should be used to find the input files to run
   /// checks against.
diff --git a/packages/flutter_tools/lib/src/android/deferred_components_prebuild_validator.dart b/packages/flutter_tools/lib/src/android/deferred_components_prebuild_validator.dart
index b14e9fc4a6..30338e6e36 100644
--- a/packages/flutter_tools/lib/src/android/deferred_components_prebuild_validator.dart
+++ b/packages/flutter_tools/lib/src/android/deferred_components_prebuild_validator.dart
@@ -11,6 +11,7 @@ import '../base/deferred_component.dart';
 import '../base/error_handling_io.dart';
 import '../base/file_system.dart';
 import '../base/logger.dart';
+import '../base/platform.dart';
 import '../globals.dart' as globals;
 import '../project.dart';
 import '../template.dart';
@@ -31,12 +32,12 @@ class DeferredComponentsPrebuildValidator extends DeferredComponentsValidator {
   /// When [exitOnFail] is set to true, the [handleResults] and [attemptToolExit]
   /// methods will exit the tool when this validator detects a recommended
   /// change. This defaults to true.
-  DeferredComponentsPrebuildValidator(Directory projectDir, Logger logger, {
+  DeferredComponentsPrebuildValidator(Directory projectDir, Logger logger, Platform platform, {
     bool exitOnFail = true,
     String title,
     Directory templatesDir,
   }) : _templatesDir = templatesDir,
-       super(projectDir, logger, exitOnFail: exitOnFail, title: title);
+       super(projectDir, logger, platform, exitOnFail: exitOnFail, title: title);
 
   final Directory _templatesDir;
 
diff --git a/packages/flutter_tools/lib/src/android/deferred_components_validator.dart b/packages/flutter_tools/lib/src/android/deferred_components_validator.dart
index 1f80a27a93..fb2e265e39 100644
--- a/packages/flutter_tools/lib/src/android/deferred_components_validator.dart
+++ b/packages/flutter_tools/lib/src/android/deferred_components_validator.dart
@@ -2,14 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import '../base/common.dart';
 import '../base/deferred_component.dart';
 import '../base/file_system.dart';
 import '../base/logger.dart';
+import '../base/platform.dart';
 import '../base/terminal.dart';
-import '../globals.dart' as globals;
 
 /// A class to configure and run deferred component setup verification checks
 /// and tasks.
@@ -21,9 +19,9 @@ import '../globals.dart' as globals;
 /// The results of each check are handled internally as they are not meant to
 /// be run isolated.
 abstract class DeferredComponentsValidator {
-  DeferredComponentsValidator(this.projectDir, this.logger, {
+  DeferredComponentsValidator(this.projectDir, this.logger, this.platform, {
     this.exitOnFail = true,
-    String title,
+    String? title,
   }) : outputDir = projectDir
         .childDirectory('build')
         .childDirectory(kDeferredComponentsTempDirectory),
@@ -38,6 +36,8 @@ abstract class DeferredComponentsValidator {
   /// Logger to use for [displayResults] output.
   final Logger logger;
 
+  final Platform platform;
+
   /// When true, failed checks and tasks will result in [attemptToolExit]
   /// triggering [throwToolExit].
   final bool exitOnFail;
@@ -74,7 +74,7 @@ abstract class DeferredComponentsValidator {
   final List<String> diffLines;
 
   /// Tracks the new and missing loading units.
-  Map<String, dynamic> loadingUnitComparisonResults;
+  Map<String, dynamic>? loadingUnitComparisonResults;
 
   /// All files read by the validator.
   final List<File> inputs;
@@ -91,7 +91,7 @@ abstract class DeferredComponentsValidator {
   bool get changesNeeded => generatedFiles.isNotEmpty
     || modifiedFiles.isNotEmpty
     || invalidFiles.isNotEmpty
-    || (loadingUnitComparisonResults != null && !(loadingUnitComparisonResults['match'] as bool));
+    || (loadingUnitComparisonResults != null && !(loadingUnitComparisonResults!['match'] as bool));
 
   /// Handles the results of all executed checks by calling [displayResults] and
   /// [attemptToolExit].
@@ -163,7 +163,7 @@ abstract class DeferredComponentsValidator {
 The above files have been placed into `build/$kDeferredComponentsTempDirectory`,
 a temporary directory. The files should be reviewed and moved into the project's
 `android` directory.''');
-        if (diffLines != null && diffLines.isNotEmpty && !globals.platform.isWindows) {
+        if (diffLines != null && diffLines.isNotEmpty && !platform.isWindows) {
           logger.printStatus(r'''
 
 The recommended changes can be quickly applied by running:
@@ -175,21 +175,21 @@ The recommended changes can be quickly applied by running:
       }
       // Log loading unit golden changes, if any.
       if (loadingUnitComparisonResults != null) {
-        if ((loadingUnitComparisonResults['new'] as List<LoadingUnit>).isNotEmpty) {
+        if ((loadingUnitComparisonResults!['new'] as List<LoadingUnit>).isNotEmpty) {
           logger.printStatus('New loading units were found:', emphasis: true);
-          for (final LoadingUnit unit in loadingUnitComparisonResults['new'] as List<LoadingUnit>) {
+          for (final LoadingUnit unit in loadingUnitComparisonResults!['new'] as List<LoadingUnit>) {
             logger.printStatus(unit.toString(), color: TerminalColor.grey, indent: 2);
           }
           logger.printStatus('');
         }
-        if ((loadingUnitComparisonResults['missing'] as Set<LoadingUnit>).isNotEmpty) {
+        if ((loadingUnitComparisonResults!['missing'] as Set<LoadingUnit>).isNotEmpty) {
           logger.printStatus('Previously existing loading units no longer exist:', emphasis: true);
-          for (final LoadingUnit unit in loadingUnitComparisonResults['missing'] as Set<LoadingUnit>) {
+          for (final LoadingUnit unit in loadingUnitComparisonResults!['missing'] as Set<LoadingUnit>) {
             logger.printStatus(unit.toString(), color: TerminalColor.grey, indent: 2);
           }
           logger.printStatus('');
         }
-        if (loadingUnitComparisonResults['match'] as bool) {
+        if (loadingUnitComparisonResults!['match'] as bool) {
           logger.printStatus('No change in generated loading units.\n');
         } else {
           logger.printStatus('''
diff --git a/packages/flutter_tools/lib/src/base/deferred_component.dart b/packages/flutter_tools/lib/src/base/deferred_component.dart
index 64a990385d..4bd63279bc 100644
--- a/packages/flutter_tools/lib/src/base/deferred_component.dart
+++ b/packages/flutter_tools/lib/src/base/deferred_component.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/file_system.dart';
 import '../base/logger.dart';
 import '../convert.dart';
@@ -14,7 +10,7 @@ import '../convert.dart';
 /// the app's pubspec.yaml.
 class DeferredComponent {
   DeferredComponent({
-    @required this.name,
+    required this.name,
     this.libraries = const <String>[],
     this.assets = const <Uri>[],
   }) : _assigned = false;
@@ -49,8 +45,8 @@ class DeferredComponent {
   /// unassigned and should not be used for any tasks that require loading unit information.
   /// When using [loadingUnits], [assigned] should be checked first. Loading units can be
   /// assigned with [assignLoadingUnits].
-  Set<LoadingUnit> get loadingUnits => _loadingUnits;
-  Set<LoadingUnit> _loadingUnits;
+  Set<LoadingUnit>? get loadingUnits => _loadingUnits;
+  Set<LoadingUnit>? _loadingUnits;
 
   /// Indicates if the component has loading units assigned.
   ///
@@ -81,7 +77,7 @@ class DeferredComponent {
     for (final String lib in libraries) {
       for (final LoadingUnit loadingUnit in allLoadingUnits) {
         if (loadingUnit.libraries.contains(lib)) {
-          _loadingUnits.add(loadingUnit);
+          _loadingUnits!.add(loadingUnit);
         }
       }
     }
@@ -97,7 +93,7 @@ class DeferredComponent {
     }
     if (loadingUnits != null && _assigned) {
       out.write('\n  LoadingUnits:');
-      for (final LoadingUnit loadingUnit in loadingUnits) {
+      for (final LoadingUnit loadingUnit in loadingUnits!) {
         out.write('\n    - ${loadingUnit.id}');
       }
     }
@@ -117,8 +113,8 @@ class LoadingUnit {
   /// Loading units must include an [id] and [libraries]. The [path] is only present when
   /// parsing the loading unit from a laoding unit manifest produced by gen_snapshot.
   LoadingUnit({
-    @required this.id,
-    @required this.libraries,
+    required this.id,
+    required this.libraries,
     this.path,
   });
 
@@ -132,7 +128,7 @@ class LoadingUnit {
   ///
   /// This value may be null when the loading unit is parsed from a
   /// `deferred_components_golden.yaml` file, which does not store the path.
-  final String path;
+  final String? path;
 
   /// Returns a human readable string representation of this LoadingUnit, ignoring
   /// the [path] field. The [path] is not included as it is not relevant when the
@@ -156,7 +152,7 @@ class LoadingUnit {
   ///
   /// This will read all existing loading units for every provided abi. If no abis are
   /// provided, loading units for all abis will be parsed.
-  static List<LoadingUnit> parseGeneratedLoadingUnits(Directory outputDir, Logger logger, {List<String> abis}) {
+  static List<LoadingUnit> parseGeneratedLoadingUnits(Directory outputDir, Logger logger, {List<String>? abis}) {
     final List<LoadingUnit> loadingUnits = <LoadingUnit>[];
     final List<FileSystemEntity> files = outputDir.listSync(recursive: true);
     for (final FileSystemEntity fileEntity in files) {
@@ -190,7 +186,7 @@ class LoadingUnit {
     }
     // Read gen_snapshot manifest
     final String fileString = manifestFile.readAsStringSync();
-    Map<String, dynamic> manifest;
+    Map<String, dynamic>? manifest;
     try {
       manifest = jsonDecode(fileString) as Map<String, dynamic>;
     } on FormatException catch (e) {
diff --git a/packages/flutter_tools/lib/src/build_system/build_system.dart b/packages/flutter_tools/lib/src/build_system/build_system.dart
index d9900e7222..de7c1c0cc6 100644
--- a/packages/flutter_tools/lib/src/build_system/build_system.dart
+++ b/packages/flutter_tools/lib/src/build_system/build_system.dart
@@ -330,6 +330,7 @@ class Environment {
     @required Logger logger,
     @required Artifacts artifacts,
     @required ProcessManager processManager,
+    @required Platform platform,
     @required String engineVersion,
     Directory buildDir,
     Map<String, String> defines = const <String, String>{},
@@ -368,6 +369,7 @@ class Environment {
       logger: logger,
       artifacts: artifacts,
       processManager: processManager,
+      platform: platform,
       engineVersion: engineVersion,
       inputs: inputs,
     );
@@ -386,6 +388,7 @@ class Environment {
     Map<String, String> defines = const <String, String>{},
     Map<String, String> inputs = const <String, String>{},
     String engineVersion,
+    Platform platform,
     @required FileSystem fileSystem,
     @required Logger logger,
     @required Artifacts artifacts,
@@ -403,6 +406,7 @@ class Environment {
       logger: logger,
       artifacts: artifacts,
       processManager: processManager,
+      platform: platform ?? FakePlatform(),
       engineVersion: engineVersion,
     );
   }
@@ -416,6 +420,7 @@ class Environment {
     @required this.defines,
     @required this.flutterRootDir,
     @required this.processManager,
+    @required this.platform,
     @required this.logger,
     @required this.fileSystem,
     @required this.artifacts,
@@ -490,6 +495,8 @@ class Environment {
 
   final ProcessManager processManager;
 
+  final Platform platform;
+
   final Logger logger;
 
   final Artifacts artifacts;
diff --git a/packages/flutter_tools/lib/src/bundle.dart b/packages/flutter_tools/lib/src/bundle.dart
index 8263c32a51..f290fa27f6 100644
--- a/packages/flutter_tools/lib/src/bundle.dart
+++ b/packages/flutter_tools/lib/src/bundle.dart
@@ -160,6 +160,7 @@ Future<void> buildWithAssemble({
     fileSystem: globals.fs,
     logger: globals.logger,
     processManager: globals.processManager,
+    platform: globals.platform,
   );
   final Target target = buildMode == BuildMode.debug
     ? const CopyFlutterBundle()
diff --git a/packages/flutter_tools/lib/src/commands/assemble.dart b/packages/flutter_tools/lib/src/commands/assemble.dart
index 6219aee73b..9be2ea88a1 100644
--- a/packages/flutter_tools/lib/src/commands/assemble.dart
+++ b/packages/flutter_tools/lib/src/commands/assemble.dart
@@ -239,6 +239,7 @@ class AssembleCommand extends FlutterCommand {
       fileSystem: globals.fs,
       logger: globals.logger,
       processManager: globals.processManager,
+      platform: globals.platform,
       engineVersion: globals.artifacts.isLocalEngine
         ? null
         : globals.flutterVersion.engineRevision
diff --git a/packages/flutter_tools/lib/src/commands/build_appbundle.dart b/packages/flutter_tools/lib/src/commands/build_appbundle.dart
index 81e15bff25..b7660b0de1 100644
--- a/packages/flutter_tools/lib/src/commands/build_appbundle.dart
+++ b/packages/flutter_tools/lib/src/commands/build_appbundle.dart
@@ -116,6 +116,7 @@ class BuildAppBundleCommand extends BuildSubCommand {
       final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
         FlutterProject.current().directory,
         globals.logger,
+        globals.platform,
         title: 'Deferred components prebuild validation',
         exitOnFail: true,
       );
diff --git a/packages/flutter_tools/lib/src/commands/build_ios_framework.dart b/packages/flutter_tools/lib/src/commands/build_ios_framework.dart
index aed1d63eb6..c3f191e3fb 100644
--- a/packages/flutter_tools/lib/src/commands/build_ios_framework.dart
+++ b/packages/flutter_tools/lib/src/commands/build_ios_framework.dart
@@ -382,6 +382,7 @@ end
           fileSystem: globals.fs,
           logger: globals.logger,
           processManager: globals.processManager,
+          platform: globals.platform,
           engineVersion: globals.artifacts.isLocalEngine
               ? null
               : globals.flutterVersion.engineRevision,
diff --git a/packages/flutter_tools/lib/src/commands/packages.dart b/packages/flutter_tools/lib/src/commands/packages.dart
index ec68415fe8..2af50c07ec 100644
--- a/packages/flutter_tools/lib/src/commands/packages.dart
+++ b/packages/flutter_tools/lib/src/commands/packages.dart
@@ -118,6 +118,7 @@ class PackagesGetCommand extends FlutterCommand {
         flutterRootDir: globals.fs.directory(Cache.flutterRoot),
         outputDir: globals.fs.directory(getBuildDirectory()),
         processManager: globals.processManager,
+        platform: globals.platform,
         projectDir: flutterProject.directory,
       );
 
@@ -323,6 +324,7 @@ class PackagesInteractiveGetCommand extends FlutterCommand {
         flutterRootDir: globals.fs.directory(Cache.flutterRoot),
         outputDir: globals.fs.directory(getBuildDirectory()),
         processManager: globals.processManager,
+        platform: globals.platform,
         projectDir: flutterProject.directory,
       );
 
diff --git a/packages/flutter_tools/lib/src/resident_runner.dart b/packages/flutter_tools/lib/src/resident_runner.dart
index ee34257b64..202b382346 100644
--- a/packages/flutter_tools/lib/src/resident_runner.dart
+++ b/packages/flutter_tools/lib/src/resident_runner.dart
@@ -919,6 +919,7 @@ abstract class ResidentRunner {
       flutterRootDir: globals.fs.directory(Cache.flutterRoot),
       outputDir: globals.fs.directory(getBuildDirectory()),
       processManager: globals.processManager,
+      platform: globals.platform,
       projectDir: globals.fs.currentDirectory,
     );
     _lastBuild = await globals.buildSystem.buildIncremental(
diff --git a/packages/flutter_tools/lib/src/runner/flutter_command.dart b/packages/flutter_tools/lib/src/runner/flutter_command.dart
index 299aaae53b..d8748d560e 100644
--- a/packages/flutter_tools/lib/src/runner/flutter_command.dart
+++ b/packages/flutter_tools/lib/src/runner/flutter_command.dart
@@ -1158,6 +1158,7 @@ abstract class FlutterCommand extends Command<void> {
         flutterRootDir: globals.fs.directory(Cache.flutterRoot),
         outputDir: globals.fs.directory(getBuildDirectory()),
         processManager: globals.processManager,
+        platform: globals.platform,
         projectDir: project.directory,
       );
 
diff --git a/packages/flutter_tools/lib/src/web/compile.dart b/packages/flutter_tools/lib/src/web/compile.dart
index 4edfb19441..5b406a8052 100644
--- a/packages/flutter_tools/lib/src/web/compile.dart
+++ b/packages/flutter_tools/lib/src/web/compile.dart
@@ -64,6 +64,7 @@ Future<void> buildWeb(
       fileSystem: globals.fs,
       logger: globals.logger,
       processManager: globals.processManager,
+      platform: globals.platform,
       cacheDir: globals.cache.getRoot(),
       engineVersion: globals.artifacts.isLocalEngine
         ? null
diff --git a/packages/flutter_tools/test/general.shard/android/deferred_components_gen_snapshot_validator_test.dart b/packages/flutter_tools/test/general.shard/android/deferred_components_gen_snapshot_validator_test.dart
index 99f1902f90..3ba668a87b 100644
--- a/packages/flutter_tools/test/general.shard/android/deferred_components_gen_snapshot_validator_test.dart
+++ b/packages/flutter_tools/test/general.shard/android/deferred_components_gen_snapshot_validator_test.dart
@@ -10,6 +10,7 @@ import 'package:flutter_tools/src/android/deferred_components_validator.dart';
 import 'package:flutter_tools/src/base/deferred_component.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/targets/common.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
@@ -35,6 +36,7 @@ void main() {
       fileSystem: fileSystem,
       logger: logger,
       processManager: globals.processManager,
+      platform: FakePlatform(),
       engineVersion: 'invalidEngineVersion',
     );
     return result;
diff --git a/packages/flutter_tools/test/general.shard/android/deferred_components_prebuild_validator_test.dart b/packages/flutter_tools/test/general.shard/android/deferred_components_prebuild_validator_test.dart
index b9a7edcf49..d3a93d5ce1 100644
--- a/packages/flutter_tools/test/general.shard/android/deferred_components_prebuild_validator_test.dart
+++ b/packages/flutter_tools/test/general.shard/android/deferred_components_prebuild_validator_test.dart
@@ -10,6 +10,7 @@ import 'package:flutter_tools/src/android/deferred_components_validator.dart';
 import 'package:flutter_tools/src/base/deferred_component.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/base/platform.dart';
 
 import '../../src/common.dart';
 import '../../src/context.dart';
@@ -18,6 +19,7 @@ void main() {
   FileSystem fileSystem;
   BufferLogger logger;
   Directory projectDir;
+  Platform platform;
   Directory flutterRootDir;
 
   setUp(() {
@@ -25,12 +27,14 @@ void main() {
     logger = BufferLogger.test();
     projectDir = fileSystem.directory('/project');
     flutterRootDir = fileSystem.directory('/flutter_root');
+    platform = FakePlatform();
   });
 
   testWithoutContext('No checks passes', () async {
     final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
       projectDir,
       logger,
+      platform,
       exitOnFail: false,
       title: 'test check',
     );
@@ -43,6 +47,7 @@ void main() {
     final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
       projectDir,
       logger,
+      platform,
       exitOnFail: false,
       title: 'test check',
     );
@@ -67,6 +72,7 @@ void main() {
     final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
       projectDir,
       logger,
+      platform,
       exitOnFail: false,
       title: 'test check',
       templatesDir: templatesDir,
@@ -105,6 +111,7 @@ void main() {
     final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
       projectDir,
       logger,
+      platform,
       exitOnFail: false,
       title: 'test check',
       templatesDir: templatesDir,
@@ -128,7 +135,7 @@ void main() {
     expect(logger.statusText.contains('build/${DeferredComponentsValidator.kDeferredComponentsTempDirectory}/component1/src/main/AndroidManifest.xml\n'), true);
   });
 
-  testUsingContext('androidComponentSetup all files exist passes', () async {
+  testWithoutContext('androidComponentSetup all files exist passes', () async {
     final Directory templatesDir = flutterRootDir.childDirectory('templates').childDirectory('deferred_component');
     final File buildGradleTemplate = templatesDir.childFile('build.gradle.tmpl');
     final File androidManifestTemplate = templatesDir.childDirectory('src').childDirectory('main').childFile('AndroidManifest.xml.tmpl');
@@ -143,6 +150,7 @@ void main() {
     final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
       projectDir,
       logger,
+      platform,
       exitOnFail: false,
       title: 'test check',
       templatesDir: templatesDir,
@@ -175,6 +183,7 @@ void main() {
     final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
       projectDir,
       logger,
+      platform,
       exitOnFail: false,
       title: 'test check',
     );
@@ -242,6 +251,7 @@ void main() {
     final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
       projectDir,
       logger,
+      platform,
       exitOnFail: false,
       title: 'test check',
     );