[flutter_tools] initial support for enable experiment, run, apk, ios, macos (#54617)

dev/bots/analyze.dart

@@ -605,6 +605,7 @@ Future<void> verifyNoTrailingSpaces(String workingDirectory, { int minimumMatche
     .where((File file) => path.extension(file.path) != '.jpg')
     .where((File file) => path.extension(file.path) != '.ico')
     .where((File file) => path.extension(file.path) != '.jar')
+    .where((File file) => path.extension(file.path) != '.swp')
     .toList();
   final List<String> problems = <String>[];
   for (final File file in files) {
@@ -1299,5 +1300,6 @@ bool _isGeneratedPluginRegistrant(File file) {
   return !file.path.contains('.pub-cache')
       && (filename == 'GeneratedPluginRegistrant.java' ||
           filename == 'GeneratedPluginRegistrant.h' ||
-          filename == 'GeneratedPluginRegistrant.m');
+          filename == 'GeneratedPluginRegistrant.m' ||
+          filename == 'generated_plugin_registrant.dart');
 }

dev/bots/test.dart

@@ -9,6 +9,7 @@ import 'dart:math' as math;
 import 'package:googleapis/bigquery/v2.dart' as bq;
 import 'package:googleapis_auth/auth_io.dart' as auth;
 import 'package:http/http.dart' as http;
+import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;
 
 import 'browser.dart';
@@ -287,21 +288,27 @@ Future<void> _runToolTests() async {
 /// we can build when there are spaces in the path name for the Flutter SDK and
 /// target app.
 Future<void> _runBuildTests() async {
-  final Stream<FileSystemEntity> exampleDirectories = Directory(path.join(flutterRoot, 'examples')).list();
-  await for (final FileSystemEntity fileEntity in exampleDirectories) {
+  final List<FileSystemEntity> exampleDirectories = Directory(path.join(flutterRoot, 'examples')).listSync()
+    ..add(Directory(path.join(flutterRoot, 'dev', 'integration_tests', 'non_nullable')));
+  for (final FileSystemEntity fileEntity in exampleDirectories) {
     if (fileEntity is! Directory) {
       continue;
     }
     final String examplePath = fileEntity.path;
+    final bool hasNullSafety = File(path.join(examplePath, 'null_safety')).existsSync();
+    final List<String> additionalArgs = hasNullSafety
+      ? <String>['--enable-experiment', 'non-nullable']
+      : <String>[];
     if (Directory(path.join(examplePath, 'android')).existsSync()) {
-      await _flutterBuildAot(examplePath);
-      await _flutterBuildApk(examplePath);
+      await _flutterBuildApk(examplePath, release: false, additionalArgs: additionalArgs);
+      await _flutterBuildApk(examplePath, release: true, additionalArgs: additionalArgs);
     } else {
-      print('Example project ${path.basename(examplePath)} has no android directory, skipping aot and apk');
+      print('Example project ${path.basename(examplePath)} has no android directory, skipping apk');
     }
     if (Platform.isMacOS) {
       if (Directory(path.join(examplePath, 'ios')).existsSync()) {
-        await _flutterBuildIpa(examplePath);
+        await _flutterBuildIpa(examplePath, release: false, additionalArgs: additionalArgs);
+        await _flutterBuildIpa(examplePath, release: true, additionalArgs: additionalArgs);
       } else {
         print('Example project ${path.basename(examplePath)} has no ios directory, skipping ipa');
       }
@@ -323,23 +330,30 @@ Future<void> _runBuildTests() async {
   }
 }
 
-Future<void> _flutterBuildAot(String relativePathToApplication) async {
-  print('${green}Testing AOT build$reset for $cyan$relativePathToApplication$reset...');
-  await runCommand(flutter,
-    <String>['build', 'aot', '-v'],
-    workingDirectory: path.join(flutterRoot, relativePathToApplication),
-  );
-}
-
-Future<void> _flutterBuildApk(String relativePathToApplication) async {
+Future<void> _flutterBuildApk(String relativePathToApplication, {
+  @required bool release,
+  List<String> additionalArgs = const <String>[],
+}) async {
   print('${green}Testing APK --debug build$reset for $cyan$relativePathToApplication$reset...');
   await runCommand(flutter,
-    <String>['build', 'apk', '--debug', '-v'],
+    <String>[
+      'build',
+      'apk',
+      ...additionalArgs,
+      if (release)
+        '--release'
+      else
+        '--debug',
+      '-v',
+    ],
     workingDirectory: path.join(flutterRoot, relativePathToApplication),
   );
 }
 
-Future<void> _flutterBuildIpa(String relativePathToApplication) async {
+Future<void> _flutterBuildIpa(String relativePathToApplication, {
+  @required bool release,
+  List<String> additionalArgs = const <String>[],
+}) async {
   assert(Platform.isMacOS);
   print('${green}Testing IPA build$reset for $cyan$relativePathToApplication$reset...');
   // Install Cocoapods.  We don't have these checked in for the examples,
@@ -355,7 +369,17 @@ Future<void> _flutterBuildIpa(String relativePathToApplication) async {
     );
   }
   await runCommand(flutter,
-    <String>['build', 'ios', '--no-codesign', '--debug', '-v'],
+    <String>[
+      'build',
+      'ios',
+      ...additionalArgs,
+      '--no-codesign',
+      if (release)
+        '--release'
+      else
+        '--debug',
+      '-v',
+    ],
     workingDirectory: path.join(flutterRoot, relativePathToApplication),
   );
 }
@@ -590,6 +614,7 @@ Future<void> _runWebIntegrationTests() async {
   await _runWebDebugTest('lib/stack_trace.dart');
   await _runWebDebugTest('lib/web_directory_loading.dart');
   await _runWebDebugTest('test/test.dart');
+  await _runWebDebugTest('lib/null_safe_main.dart', enableNullSafety: true);
   await _runWebDebugTest('lib/web_define_loading.dart',
     additionalArguments: <String>[
       '--dart-define=test.valueA=Example',
@@ -692,6 +717,7 @@ Future<void> _runWebReleaseTest(String target, {
 ///
 /// Instead, we use `flutter run --debug` and sniff out the standard output.
 Future<void> _runWebDebugTest(String target, {
+  bool enableNullSafety = false,
   List<String> additionalArguments = const<String>[],
 }) async {
   final String testAppDirectory = path.join(flutterRoot, 'dev', 'integration_tests', 'web');
@@ -702,6 +728,11 @@ Future<void> _runWebDebugTest(String target, {
     <String>[
       'run',
       '--debug',
+      if (enableNullSafety)
+        ...<String>[
+          '--enable-experiment',
+          'non-nullable',
+        ],
       '-d',
       'chrome',
       '--web-run-headless',

dev/integration_tests/non_nullable/.gitignore

+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.buildlog/
+.history
+.svn/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
+.dart_tool/
+.flutter-plugins
+.flutter-plugins-dependencies
+.packages
+.pub-cache/
+.pub/
+/build/
+
+# Web related
+lib/generated_plugin_registrant.dart
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Exceptions to above rules.
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages

dev/integration_tests/non_nullable/analysis_options.yaml

+# Exclude lib/main.dart to avoid warnings about the non_nullable
+# experiment before it is enabled.
+analyzer:
+  exclude:
+    - lib/main.dart

dev/integration_tests/non_nullable/android/.gitignore

+gradle-wrapper.jar
+/.gradle
+/captures/
+/gradlew
+/gradlew.bat
+/local.properties
+GeneratedPluginRegistrant.java

dev/integration_tests/non_nullable/android/app/build.gradle

+// 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.
+
+def localProperties = new Properties()
+def localPropertiesFile = rootProject.file('local.properties')
+if (localPropertiesFile.exists()) {
+    localPropertiesFile.withReader('UTF-8') { reader ->
+        localProperties.load(reader)
+    }
+}
+
+def flutterRoot = localProperties.getProperty('flutter.sdk')
+if (flutterRoot == null) {
+    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
+}
+
+def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
+if (flutterVersionCode == null) {
+    flutterVersionCode = '1'
+}
+
+def flutterVersionName = localProperties.getProperty('flutter.versionName')
+if (flutterVersionName == null) {
+    flutterVersionName = '1.0'
+}
+
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
+
+android {
+    compileSdkVersion 28
+
+    sourceSets {
+        main.java.srcDirs += 'src/main/kotlin'
+    }
+
+    lintOptions {
+        disable 'InvalidPackage'
+    }
+
+    defaultConfig {
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
+        applicationId "com.example.non_nullable"
+        minSdkVersion 16
+        targetSdkVersion 28
+        versionCode flutterVersionCode.toInteger()
+        versionName flutterVersionName
+    }
+
+    buildTypes {
+        release {
+            // TODO: Add your own signing config for the release build.
+            // Signing with the debug keys for now, so `flutter run --release` works.
+            signingConfig signingConfigs.debug
+        }
+    }
+}
+
+flutter {
+    source '../..'
+}
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+}

dev/integration_tests/non_nullable/android/app/src/debug/AndroidManifest.xml

+<!-- 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. -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.non_nullable">
+    <!-- Flutter needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

dev/integration_tests/non_nullable/android/app/src/main/AndroidManifest.xml

+<!-- 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. -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.non_nullable">
+    <!-- io.flutter.app.FlutterApplication is an android.app.Application that
+         calls FlutterMain.startInitialization(this); in its onCreate method.
+         In most cases you can leave this as-is, but you if you want to provide
+         additional functionality it is fine to subclass or reimplement
+         FlutterApplication and put your custom class here. -->
+    <application
+        android:name="io.flutter.app.FlutterApplication"
+        android:label="non_nullable"
+        android:icon="@mipmap/ic_launcher">
+        <activity
+            android:name=".MainActivity"
+            android:launchMode="singleTop"
+            android:theme="@style/NormalTheme"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
+            android:hardwareAccelerated="true"
+            android:windowSoftInputMode="adjustResize">
+            <!-- Specifies an Android theme to apply to this Activity as soon as
+                 the Android process has started. This theme is visible to the user
+                 while the Flutter UI initializes. After that, this theme continues
+                 to determine the Window background behind the Flutter UI. -->
+            <meta-data
+              android:name="io.flutter.embedding.android.NormalTheme"
+              android:resource="@style/NormalTheme"
+              />
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+        <!-- Don't delete the meta-data below.
+             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
+    </application>
+</manifest>

dev/integration_tests/non_nullable/android/app/src/main/kotlin/com/example/non_nullable/MainActivity.kt

+package com.example.non_nullable
+
+import io.flutter.embedding.android.FlutterActivity
+
+class MainActivity: FlutterActivity() {
+}

dev/integration_tests/non_nullable/android/app/src/main/res/drawable/launch_background.xml

+<!-- 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. -->
+
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="@android:color/white" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>

dev/integration_tests/non_nullable/android/app/src/main/res/values/styles.xml

+<!-- 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. -->
+
+<resources>
+    <!-- Theme applied to the Android Window as soon as the process has started.
+         This theme determines the color of the Android Window while your
+         Flutter UI initializes, as well as behind your Flutter UI while its
+         running.
+
+         This Theme is only used starting with V2 of Flutter's Android embedding. -->
+    <style name="NormalTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <item name="android:windowBackground">@android:color/white</item>
+    </style>
+</resources>

dev/integration_tests/non_nullable/android/app/src/profile/AndroidManifest.xml

+<!-- 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. -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.non_nullable">
+    <!-- Flutter needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

dev/integration_tests/non_nullable/android/build.gradle

+// 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.
+
+buildscript {
+    ext.kotlin_version = '1.3.50'
+    repositories {
+        google()
+        jcenter()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        jcenter()
+    }
+}
+
+rootProject.buildDir = '../build'
+subprojects {
+    project.buildDir = "${rootProject.buildDir}/${project.name}"
+}
+subprojects {
+    project.evaluationDependsOn(':app')
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}

dev/integration_tests/non_nullable/android/gradle.properties

+org.gradle.jvmargs=-Xmx1536M
+android.enableR8=true
+android.useAndroidX=true
+android.enableJetifier=true

dev/integration_tests/non_nullable/android/gradle/wrapper/gradle-wrapper.properties

+#Fri Jun 23 08:50:38 CEST 2017
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip

dev/integration_tests/non_nullable/android/settings.gradle

+// 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.
+
+include ':app'
+
+def localPropertiesFile = new File(rootProject.projectDir, "local.properties")
+def properties = new Properties()
+
+assert localPropertiesFile.exists()
+localPropertiesFile.withReader("UTF-8") { reader -> properties.load(reader) }
+
+def flutterSdkPath = properties.getProperty("flutter.sdk")
+assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
+apply from: "$flutterSdkPath/packages/flutter_tools/gradle/app_plugin_loader.gradle"

dev/integration_tests/non_nullable/ios/.gitignore

+*.mode1v3
+*.mode2v3
+*.moved-aside
+*.pbxuser
+*.perspectivev3
+**/*sync/
+.sconsign.dblite
+.tags*
+**/.vagrant/
+**/DerivedData/
+Icon?
+**/Pods/
+**/.symlinks/
+profile
+xcuserdata
+**/.generated/
+Flutter/App.framework
+Flutter/Flutter.framework
+Flutter/Flutter.podspec
+Flutter/Generated.xcconfig
+Flutter/app.flx
+Flutter/app.zip
+Flutter/flutter_assets/
+Flutter/flutter_export_environment.sh
+ServiceDefinitions.json
+Runner/GeneratedPluginRegistrant.*
+
+# Exceptions to above rules.
+!default.mode1v3
+!default.mode2v3
+!default.pbxuser
+!default.perspectivev3

dev/integration_tests/non_nullable/ios/Flutter/AppFrameworkInfo.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>CFBundleDevelopmentRegion</key>
+  <string>$(DEVELOPMENT_LANGUAGE)</string>
+  <key>CFBundleExecutable</key>
+  <string>App</string>
+  <key>CFBundleIdentifier</key>
+  <string>io.flutter.flutter.app</string>
+  <key>CFBundleInfoDictionaryVersion</key>
+  <string>6.0</string>
+  <key>CFBundleName</key>
+  <string>App</string>
+  <key>CFBundlePackageType</key>
+  <string>FMWK</string>
+  <key>CFBundleShortVersionString</key>
+  <string>1.0</string>
+  <key>CFBundleSignature</key>
+  <string>????</string>
+  <key>CFBundleVersion</key>
+  <string>1.0</string>
+  <key>MinimumOSVersion</key>
+  <string>8.0</string>
+</dict>
+</plist>

dev/integration_tests/non_nullable/ios/Flutter/Debug.xcconfig

+#include "Generated.xcconfig"

dev/integration_tests/non_nullable/ios/Flutter/Release.xcconfig

+#include "Generated.xcconfig"

dev/integration_tests/non_nullable/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata

+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "group:Runner.xcodeproj">
+   </FileRef>
+</Workspace>

dev/integration_tests/non_nullable/ios/Runner.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

dev/integration_tests/non_nullable/ios/Runner.xcodeproj/project.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>PreviewsEnabled</key>
+	<false/>
+</dict>
+</plist>

dev/integration_tests/non_nullable/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1020"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+               BuildableName = "Runner.app"
+               BlueprintName = "Runner"
+               ReferencedContainer = "container:Runner.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+      </Testables>
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Profile"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

dev/integration_tests/non_nullable/ios/Runner.xcworkspace/contents.xcworkspacedata

+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "group:Runner.xcodeproj">
+   </FileRef>
+</Workspace>

dev/integration_tests/non_nullable/ios/Runner.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

dev/integration_tests/non_nullable/ios/Runner.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>PreviewsEnabled</key>
+	<false/>
+</dict>
+</plist>

dev/integration_tests/non_nullable/ios/Runner/AppDelegate.swift

+// 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 UIKit
+import Flutter
+
+@UIApplicationMain
+@objc class AppDelegate: FlutterAppDelegate {
+  override func application(
+    _ application: UIApplication,
+    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
+  ) -> Bool {
+    GeneratedPluginRegistrant.register(with: self)
+    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
+  }
+}

dev/integration_tests/non_nullable/ios/Runner/Assets.xcassets/AppIcon.appiconset/Contents.json

+{
+  "images" : [
+    {
+      "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-20x20@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-20x20@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-40x40@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-40x40@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-60x60@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-60x60@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "20x20",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-20x20@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "20x20",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-20x20@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-29x29@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-29x29@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-40x40@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-40x40@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "76x76",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-76x76@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "76x76",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-76x76@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "83.5x83.5",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-83.5x83.5@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "1024x1024",
+      "idiom" : "ios-marketing",
+      "filename" : "Icon-App-1024x1024@1x.png",
+      "scale" : "1x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

dev/integration_tests/non_nullable/ios/Runner/Assets.xcassets/LaunchImage.imageset/Contents.json

+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage.png",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage@3x.png",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

dev/integration_tests/non_nullable/ios/Runner/Assets.xcassets/LaunchImage.imageset/README.md

+# Launch Screen Assets
+
+You can customize the launch screen with your own desired assets by replacing the image files in this directory.
+
+You can also do it by opening your Flutter project's Xcode project with `open ios/Runner.xcworkspace`, selecting `Runner/Assets.xcassets` in the Project Navigator and dropping in the desired images.
\ No newline at end of file

dev/integration_tests/non_nullable/ios/Runner/Base.lproj/LaunchScreen.storyboard

+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="12121" systemVersion="16G29" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" colorMatched="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12089"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="Ydg-fD-yQy"/>
+                        <viewControllerLayoutGuide type="bottom" id="xbc-2k-c8Z"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <imageView opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" image="LaunchImage" translatesAutoresizingMaskIntoConstraints="NO" id="YRO-k0-Ey4">
+                            </imageView>
+                        </subviews>
+                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <constraints>
+                            <constraint firstItem="YRO-k0-Ey4" firstAttribute="centerX" secondItem="Ze5-6b-2t3" secondAttribute="centerX" id="1a2-6s-vTC"/>
+                            <constraint firstItem="YRO-k0-Ey4" firstAttribute="centerY" secondItem="Ze5-6b-2t3" secondAttribute="centerY" id="4X2-HB-R7a"/>
+                        </constraints>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="53" y="375"/>
+        </scene>
+    </scenes>
+    <resources>
+        <image name="LaunchImage" width="168" height="185"/>
+    </resources>
+</document>

dev/integration_tests/non_nullable/ios/Runner/Base.lproj/Main.storyboard

+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="10117" systemVersion="15F34" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" initialViewController="BYZ-38-t0r">
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="10085"/>
+    </dependencies>
+    <scenes>
+        <!--Flutter View Controller-->
+        <scene sceneID="tne-QT-ifu">
+            <objects>
+                <viewController id="BYZ-38-t0r" customClass="FlutterViewController" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="y3c-jy-aDJ"/>
+                        <viewControllerLayoutGuide type="bottom" id="wfy-db-euE"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="8bC-Xf-vdC">
+                        <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/>
+            </objects>
+        </scene>
+    </scenes>
+</document>

dev/integration_tests/non_nullable/ios/Runner/Info.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>non_nullable</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>$(FLUTTER_BUILD_NAME)</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string>$(FLUTTER_BUILD_NUMBER)</string>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIMainStoryboardFile</key>
+	<string>Main</string>
+	<key>UISupportedInterfaceOrientations</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UISupportedInterfaceOrientations~ipad</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationPortraitUpsideDown</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UIViewControllerBasedStatusBarAppearance</key>
+	<false/>
+</dict>
+</plist>

dev/integration_tests/non_nullable/ios/Runner/Runner-Bridging-Header.h

+// 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 "GeneratedPluginRegistrant.h"

dev/integration_tests/non_nullable/lib/main.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.
+
+// @dart=2.9
+import 'package:flutter/material.dart';
+
+String? unused;
+
+void main() {
+  runApp(MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Flutter Demo',
+      theme: ThemeData(
+        primarySwatch: Colors.blue,
+        visualDensity: VisualDensity.adaptivePlatformDensity,
+      ),
+      home: const Center(child: Text('hello, world'))
+    );
+  }
+}

dev/integration_tests/non_nullable/pubspec.yaml

+name: non_nullable
+description: A new Flutter project.
+
+publish_to: 'none' # Remove this line if you wish to publish to pub.dev
+version: 1.0.0+1
+
+environment:
+  sdk: ">=2.7.0 <3.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  cupertino_icons: 0.1.3
+
+  collection: 1.14.12 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  meta: 1.1.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  typed_data: 1.1.6 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  vector_math: 2.0.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+
+  async: 2.4.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  boolean_selector: 2.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  charcode: 1.1.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  clock: 1.0.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  fake_async: 1.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  matcher: 0.12.6 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  path: 1.7.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  source_span: 1.7.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  stack_trace: 1.9.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  stream_channel: 2.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  string_scanner: 1.0.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  term_glyph: 1.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  test_api: 0.2.15 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+
+flutter:
+  uses-material-design: true
+
+# PUBSPEC CHECKSUM: 7c67

dev/integration_tests/non_nullable/web/index.html

+<!DOCTYPE HTML>
+<!-- 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. -->
+
+<html>
+<head>
+  <meta charset="UTF-8">
+  <meta content="IE=Edge" http-equiv="X-UA-Compatible">
+  <meta name="description" content="A new Flutter project.">
+
+  <!-- iOS meta tags & icons -->
+  <meta name="apple-mobile-web-app-capable" content="yes">
+  <meta name="apple-mobile-web-app-status-bar-style" content="black">
+  <meta name="apple-mobile-web-app-title" content="non_nullable">
+  <link rel="apple-touch-icon" href="icons/Icon-192.png">
+
+  <!-- Favicon -->
+  <link rel="shortcut icon" type="image/png" href="favicon.png"/>
+
+  <title>non_nullable</title>
+  <link rel="manifest" href="manifest.json">
+</head>
+<body>
+  <!-- This script installs service_worker.js to provide PWA functionality to
+       application. For more information, see:
+       https://developers.google.com/web/fundamentals/primers/service-workers -->
+  <script>
+    if ('serviceWorker' in navigator) {
+      window.addEventListener('load', function () {
+        navigator.serviceWorker.register('flutter_service_worker.js');
+      });
+    }
+  </script>
+  <script src="main.dart.js" type="application/javascript"></script>
+</body>
+</html>

dev/integration_tests/non_nullable/web/manifest.json

+{
+    "name": "non_nullable",
+    "short_name": "non_nullable",
+    "start_url": ".",
+    "display": "minimal-ui",
+    "background_color": "#0175C2",
+    "theme_color": "#0175C2",
+    "description": "A new Flutter project.",
+    "orientation": "portrait-primary",
+    "prefer_related_applications": false,
+    "icons": [
+        {
+            "src": "icons/Icon-192.png",
+            "sizes": "192x192",
+            "type": "image/png"
+        },
+        {
+            "src": "icons/Icon-512.png",
+            "sizes": "512x512",
+            "type": "image/png"
+        }
+    ]
+}

dev/integration_tests/web/analysis_options.yaml

+# Exclude lib/main.dart to avoid warnings about the non_nullable
+# experiment before it is enabled.
+analyzer:
+  exclude:
+    - lib/null_safe_main.dart

dev/integration_tests/web/lib/null_safe_main.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.
+
+// @dart=2.9
+
+String? x;
+
+void main() {
+  print('--- TEST SUCCEEDED ---');
+}

dev/integration_tests/web/pubspec.yaml

@@ -3,7 +3,7 @@ description: Integration test for web compilation.
 
 environment:
   # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
-  sdk: ">=2.0.0-dev.68.0 <3.0.0"
+  sdk: ">=2.6.0 <3.0.0"
 
 dependencies:
   flutter:

packages/flutter_tools/bin/macos_assemble.sh

@@ -84,6 +84,7 @@ RunCommand "${FLUTTER_ROOT}/bin/flutter"                                    \
     -dDartObfuscation="${dart_obfuscation_flag}"                            \
     -dSplitDebugInfo="${SPLIT_DEBUG_INFO}"                                  \
     --DartDefines="${DART_DEFINES}"                                         \
+    --ExtraGenSnapshotOptions="${EXTRA_GEN_SNAPSHOT_OPTIONS}"               \
     -dExtraFrontEndOptions="${EXTRA_FRONT_END_OPTIONS}"                     \
     --build-inputs="${build_inputs_path}"                                   \
     --build-outputs="${build_outputs_path}"                                 \

packages/flutter_tools/bin/xcode_backend.sh

@@ -186,6 +186,7 @@ BuildApp() {
     -dTrackWidgetCreation="${track_widget_creation_flag}"                 \
     -dDartObfuscation="${dart_obfuscation_flag}"                          \
     -dEnableBitcode="${bitcode_flag}"                                     \
+    --ExtraGenSnapshotOptions="${EXTRA_GEN_SNAPSHOT_OPTIONS}"             \
     --DartDefines="${DART_DEFINES}"                                       \
     -dExtraFrontEndOptions="${EXTRA_FRONT_END_OPTIONS}"                   \
     "${build_mode}_ios_bundle_flutter_assets"

packages/flutter_tools/lib/src/android/gradle.dart

@@ -315,7 +315,7 @@ Future<void> buildGradleApp({
     command.add('-Pextra-front-end-options=${buildInfo.extraFrontEndOptions.join(',')}');
   }
   if (buildInfo.extraGenSnapshotOptions != null) {
-    command.add('-Pextra-gen-snapshot-options=${buildInfo.extraGenSnapshotOptions}');
+    command.add('-Pextra-gen-snapshot-options=${buildInfo.extraGenSnapshotOptions.join(',')}');
   }
   if (buildInfo.fileSystemRoots != null && buildInfo.fileSystemRoots.isNotEmpty) {
     command.add('-Pfilesystem-roots=${buildInfo.fileSystemRoots.join('|')}');

packages/flutter_tools/lib/src/build_info.dart

@@ -24,6 +24,7 @@ class BuildInfo {
     this.splitDebugInfoPath,
     this.dartObfuscation = false,
     this.dartDefines = const <String>[],
+    this.dartExperiments = const <String>[],
     @required this.treeShakeIcons,
   });
 
@@ -79,6 +80,9 @@ class BuildInfo {
   /// [bool], [String], [int], and [double].
   final List<String> dartDefines;
 
+  /// A list of Dart experiments.
+  final List<String> dartExperiments;
+
   static const BuildInfo debug = BuildInfo(BuildMode.debug, null, treeShakeIcons: false);
   static const BuildInfo profile = BuildInfo(BuildMode.profile, null, treeShakeIcons: kIconTreeShakerEnabledDefault);
   static const BuildInfo jitRelease = BuildInfo(BuildMode.jitRelease, null, treeShakeIcons: kIconTreeShakerEnabledDefault);

packages/flutter_tools/lib/src/build_runner/resident_web_runner.dart

@@ -435,6 +435,7 @@ class _ResidentWebRunner extends ResidentWebRunner {
             debuggingOptions.buildInfo,
             debuggingOptions.initializePlatform,
             false,
+            debuggingOptions.buildInfo.dartExperiments,
           );
         }
         await device.device.startApp(
@@ -496,6 +497,7 @@ class _ResidentWebRunner extends ResidentWebRunner {
           debuggingOptions.buildInfo,
           debuggingOptions.initializePlatform,
           false,
+          debuggingOptions.buildInfo.dartExperiments,
         );
       } on ToolExit {
         return OperationResult(1, 'Failed to recompile application.');

packages/flutter_tools/lib/src/build_system/targets/ios.dart

@@ -46,8 +46,7 @@ abstract class AotAssemblyBase extends Target {
     if (environment.defines[kTargetPlatform] == null) {
       throw MissingDefineException(kTargetPlatform, 'aot_assembly');
     }
-    final List<String> extraGenSnapshotOptions = environment
-      .defines[kExtraGenSnapshotOptions]?.split(',') ?? const <String>[];
+    final List<String> extraGenSnapshotOptions = parseExtraGenSnapshotOptions(environment);
     final bool bitcode = environment.defines[kBitcodeFlag] == 'true';
     final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
     final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
@@ -438,3 +437,13 @@ Future<RunResult> createStubAppFramework(File outputFile, SdkType sdk, { bool in
     }
   }
 }
+
+/// iOS and macOS build scripts may pass extraGenSnapshotOptions as an empty
+/// string.
+List<String> parseExtraGenSnapshotOptions(Environment environment) {
+  final String value = environment.defines[kExtraGenSnapshotOptions];
+  if (value == null || value.trim().isEmpty) {
+    return <String>[];
+  }
+  return value.split(',');
+}

packages/flutter_tools/lib/src/build_system/targets/macos.dart

@@ -15,6 +15,7 @@ import '../exceptions.dart';
 import 'assets.dart';
 import 'dart.dart';
 import 'icon_tree_shaker.dart';
+import 'ios.dart';
 
 /// Copy the macOS framework to the correct copy dir by invoking 'cp -R'.
 ///
@@ -198,6 +199,7 @@ class CompileMacOSFramework extends Target {
     }
     final String splitDebugInfo = environment.defines[kSplitDebugInfo];
     final bool dartObfuscation = environment.defines[kDartObfuscation] == 'true';
+    final List<String> extraGenSnapshotOptions = parseExtraGenSnapshotOptions(environment);
     final AOTSnapshotter snapshotter = AOTSnapshotter(
       reportTimings: false,
       fileSystem: globals.fs,
@@ -216,6 +218,7 @@ class CompileMacOSFramework extends Target {
       packagesPath: environment.projectDir.childFile('.packages').path,
       splitDebugInfo: splitDebugInfo,
       dartObfuscation: dartObfuscation,
+      extraGenSnapshotOptions: extraGenSnapshotOptions,
     );
     if (result != 0) {
       throw Exception('gen shapshot failed.');

packages/flutter_tools/lib/src/build_system/targets/web.dart

@@ -27,6 +27,11 @@ const String kHasWebPlugins = 'HasWebPlugins';
 /// Valid values are O1 (lowest, profile default) to O4 (highest, release default).
 const String kDart2jsOptimization = 'Dart2jsOptimization';
 
+/// Allow specifying experiments for dart2js.
+///
+/// Multiple values should be encoded as a comma-separated list.
+const String kEnableExperiment = 'EnableExperiment';
+
 /// Whether to disable dynamic generation code to satisfy csp policies.
 const String kCspMode = 'cspMode';
 
@@ -152,11 +157,13 @@ class Dart2JSTarget extends Target {
     final String dart2jsOptimization = environment.defines[kDart2jsOptimization];
     final bool csp = environment.defines[kCspMode] == 'true';
     final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
-    final String specPath = globals.fs.path.join(globals.artifacts.getArtifactPath(Artifact.flutterWebSdk), 'libraries.json');
+    final String specPath = globals.fs.path.join(
+      globals.artifacts.getArtifactPath(Artifact.flutterWebSdk), 'libraries.json');
     final String packageFile = globalPackagesPath;
     final File outputKernel = environment.buildDir.childFile('app.dill');
     final File outputFile = environment.buildDir.childFile('main.dart.js');
     final List<String> dartDefines = parseDartDefines(environment);
+    final String enabledExperiments = environment.defines[kEnableExperiment];
 
     // Run the dart2js compilation in two stages, so that icon tree shaking can
     // parse the kernel file for web builds.
@@ -164,11 +171,17 @@ class Dart2JSTarget extends Target {
       globals.artifacts.getArtifactPath(Artifact.engineDartBinary),
       globals.artifacts.getArtifactPath(Artifact.dart2jsSnapshot),
       '--libraries-spec=$specPath',
+      if (enabledExperiments != null)
+        '--enable-experiment=$enabledExperiments',
       '-o',
       outputKernel.path,
+      '--packages=$packageFile',
+      if (buildMode == BuildMode.profile)
+        '-Ddart.vm.profile=true'
+      else
+        '-Ddart.vm.product=true',
       for (final String dartDefine in dartDefines)
         '-D$dartDefine',
-      '--packages=$packageFile',
       '--cfe-only',
       environment.buildDir.childFile('main.dart').path,
     ]);
@@ -179,6 +192,8 @@ class Dart2JSTarget extends Target {
       globals.artifacts.getArtifactPath(Artifact.engineDartBinary),
       globals.artifacts.getArtifactPath(Artifact.dart2jsSnapshot),
       '--libraries-spec=$specPath',
+      if (enabledExperiments != null)
+        '--enable-experiment=$enabledExperiments',
       if (dart2jsOptimization != null)
         '-$dart2jsOptimization'
       else

packages/flutter_tools/lib/src/commands/analyze.dart

@@ -30,7 +30,7 @@ class AnalyzeCommand extends FlutterCommand {
        _logger = logger,
        _terminal = terminal,
        _platform = platform {
-    addEnableExperimentation(verbose: verboseHelp);
+    addEnableExperimentation(hide: !verboseHelp);
     argParser.addFlag('flutter-repo',
         negatable: false,
         help: 'Include all the examples and tests from the Flutter repository.',

packages/flutter_tools/lib/src/commands/build.dart

@@ -21,19 +21,19 @@ import 'build_ios_framework.dart';
 import 'build_web.dart';
 
 class BuildCommand extends FlutterCommand {
-  BuildCommand({bool verboseHelp = false}) {
+  BuildCommand({ bool verboseHelp = false }) {
     addSubcommand(BuildAarCommand());
     addSubcommand(BuildApkCommand(verboseHelp: verboseHelp));
     addSubcommand(BuildAppBundleCommand(verboseHelp: verboseHelp));
     addSubcommand(BuildAotCommand());
-    addSubcommand(BuildIOSCommand());
+    addSubcommand(BuildIOSCommand(verboseHelp: verboseHelp));
     addSubcommand(BuildIOSFrameworkCommand(
       buildSystem: globals.buildSystem,
       bundleBuilder: BundleBuilder(),
     ));
     addSubcommand(BuildBundleCommand(verboseHelp: verboseHelp));
-    addSubcommand(BuildWebCommand());
-    addSubcommand(BuildMacosCommand());
+    addSubcommand(BuildWebCommand(verboseHelp: verboseHelp));
+    addSubcommand(BuildMacosCommand(verboseHelp: verboseHelp));
     addSubcommand(BuildLinuxCommand());
     addSubcommand(BuildWindowsCommand());
     addSubcommand(BuildFuchsiaCommand(verboseHelp: verboseHelp));

packages/flutter_tools/lib/src/commands/build_apk.dart

@@ -30,6 +30,7 @@ class BuildApkCommand extends BuildSubCommand {
     addDartObfuscationOption();
     usesDartDefineOption();
     usesExtraFrontendOptions();
+    addEnableExperimentation(hide: !verboseHelp);
     argParser
       ..addFlag('split-per-abi',
         negatable: false,

packages/flutter_tools/lib/src/commands/build_ios.dart

@@ -4,6 +4,8 @@
 
 import 'dart:async';
 
+import 'package:meta/meta.dart';
+
 import '../application_package.dart';
 import '../base/common.dart';
 import '../base/utils.dart';
@@ -17,7 +19,7 @@ import 'build.dart';
 /// or simulator. Can only be run on a macOS host. For producing deployment
 /// .ipas, see https://flutter.dev/docs/deployment/ios.
 class BuildIOSCommand extends BuildSubCommand {
-  BuildIOSCommand() {
+  BuildIOSCommand({ @required bool verboseHelp }) {
     addTreeShakeIconsFlag();
     addSplitDebugInfoOption();
     addBuildModeFlags(defaultToRelease: false);
@@ -29,6 +31,7 @@ class BuildIOSCommand extends BuildSubCommand {
     addDartObfuscationOption();
     usesDartDefineOption();
     usesExtraFrontendOptions();
+    addEnableExperimentation(hide: !verboseHelp);
     argParser
       ..addFlag('simulator',
         help: 'Build for the iOS simulator instead of the device.',

packages/flutter_tools/lib/src/commands/build_macos.dart

@@ -4,6 +4,8 @@
 
 import 'dart:async';
 
+import 'package:meta/meta.dart';
+
 import '../base/common.dart';
 import '../build_info.dart';
 import '../cache.dart';
@@ -16,7 +18,7 @@ import 'build.dart';
 
 /// A command to build a macOS desktop target through a build shell script.
 class BuildMacosCommand extends BuildSubCommand {
-  BuildMacosCommand() {
+  BuildMacosCommand({ @required bool verboseHelp }) {
     addTreeShakeIconsFlag();
     addSplitDebugInfoOption();
     usesTargetOption();
@@ -25,6 +27,7 @@ class BuildMacosCommand extends BuildSubCommand {
     usesExtraFrontendOptions();
     usesBuildNumberOption();
     usesBuildNameOption();
+    addEnableExperimentation(hide: !verboseHelp);
   }
 
   @override

packages/flutter_tools/lib/src/commands/build_web.dart

@@ -4,22 +4,27 @@
 
 import 'dart:async';
 
+import 'package:meta/meta.dart';
+
 import '../base/common.dart';
 import '../build_info.dart';
 import '../features.dart';
 import '../project.dart';
 import '../runner/flutter_command.dart'
-    show DevelopmentArtifact, FlutterCommandResult;
+    show DevelopmentArtifact, FlutterCommandResult, FlutterOptions;
 import '../web/compile.dart';
 import 'build.dart';
 
 class BuildWebCommand extends BuildSubCommand {
-  BuildWebCommand() {
+  BuildWebCommand({
+    @required bool verboseHelp,
+  }) {
     addTreeShakeIconsFlag();
     usesTargetOption();
     usesPubOption();
     addBuildModeFlags(excludeDebug: true);
     usesDartDefineOption();
+    addEnableExperimentation(hide: !verboseHelp);
     argParser.addFlag('web-initialize-platform',
         defaultsTo: true,
         negatable: true,
@@ -66,6 +71,7 @@ class BuildWebCommand extends BuildSubCommand {
       buildInfo,
       boolArg('web-initialize-platform'),
       boolArg('csp'),
+      stringsArg(FlutterOptions.kEnableExperiment),
     );
     return FlutterCommandResult.success();
   }

packages/flutter_tools/lib/src/commands/run.dart

@@ -80,6 +80,8 @@ class RunCommand extends RunCommandBase {
   RunCommand({ bool verboseHelp = false }) : super(verboseHelp: verboseHelp) {
     requiresPubspecYaml();
     usesFilesystemOptions(hide: !verboseHelp);
+    usesExtraFrontendOptions();
+    addEnableExperimentation(hide: !verboseHelp);
     argParser
       ..addFlag('start-paused',
         negatable: false,
@@ -208,11 +210,6 @@ class RunCommand extends RunCommandBase {
         help: 'Whether to quickly bootstrap applications with a minimal app. '
               'Currently this is only supported on Android devices. This option '
               'cannot be paired with --use-application-binary.'
-      )
-      ..addOption(FlutterOptions.kExtraFrontEndOptions, hide: true)
-      ..addMultiOption(FlutterOptions.kEnableExperiment,
-        splitCommas: true,
-        hide: true,
       );
   }
 

packages/flutter_tools/lib/src/ios/xcodeproj.dart

@@ -239,7 +239,16 @@ List<String> _xcodeBuildSettingsLines({
   }
 
   if (buildInfo.extraFrontEndOptions?.isNotEmpty ?? false) {
-    xcodeBuildSettings.add('EXTRA_FRONT_END_OPTIONS=${buildInfo.extraFrontEndOptions.join(',')}');
+    xcodeBuildSettings.add(
+      'EXTRA_FRONT_END_OPTIONS='
+      '${buildInfo.extraFrontEndOptions.join(',')}',
+    );
+  }
+  if (buildInfo.extraGenSnapshotOptions?.isNotEmpty ?? false) {
+    xcodeBuildSettings.add(
+      'EXTRA_GEN_SNAPSHOT_OPTIONS='
+      '${buildInfo.extraGenSnapshotOptions.join(',')}',
+    );
   }
 
   return xcodeBuildSettings;

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -470,14 +470,14 @@ abstract class FlutterCommand extends Command<void> {
     );
   }
 
-  void addEnableExperimentation({ bool verbose }) {
+  void addEnableExperimentation({ bool hide = false }) {
     argParser.addMultiOption(
       FlutterOptions.kEnableExperiment,
       help:
         'The name of an experimental Dart feature to enable. For more info '
         'see: https://github.com/dart-lang/sdk/blob/master/docs/process/'
         'experimental-flags.md',
-      hide: !verbose,
+      hide: hide,
     );
   }
 
@@ -542,18 +542,27 @@ abstract class FlutterCommand extends Command<void> {
       boolArg('track-widget-creation');
 
     final String buildNumber = argParser.options.containsKey('build-number')
-        ? stringArg('build-number')
-        : null;
+      ? stringArg('build-number')
+      : null;
 
+    final List<String> experiments =
+      argParser.options.containsKey(FlutterOptions.kEnableExperiment)
+        ? stringsArg(FlutterOptions.kEnableExperiment)
+        : <String>[];
+    final List<String> extraGenSnapshotOptions =
+      argParser.options.containsKey(FlutterOptions.kExtraGenSnapshotOptions)
+        ? stringsArg(FlutterOptions.kExtraGenSnapshotOptions)
+        : <String>[];
     final List<String> extraFrontEndOptions =
-        argParser.options.containsKey(FlutterOptions.kExtraFrontEndOptions)
-            ? stringsArg(FlutterOptions.kExtraFrontEndOptions)
-            : <String>[];
-    if (argParser.options.containsKey(FlutterOptions.kEnableExperiment) &&
-        argResults[FlutterOptions.kEnableExperiment] != null) {
-      for (final String expFlag in stringsArg(FlutterOptions.kEnableExperiment)) {
+      argParser.options.containsKey(FlutterOptions.kExtraFrontEndOptions)
+          ? stringsArg(FlutterOptions.kExtraFrontEndOptions)
+          : <String>[];
+
+    if (experiments.isNotEmpty) {
+      for (final String expFlag in experiments) {
         final String flag = '--enable-experiment=' + expFlag;
         extraFrontEndOptions.add(flag);
+        extraGenSnapshotOptions.add(flag);
       }
     }
 
@@ -579,8 +588,8 @@ abstract class FlutterCommand extends Command<void> {
       extraFrontEndOptions: extraFrontEndOptions?.isNotEmpty ?? false
         ? extraFrontEndOptions
         : null,
-      extraGenSnapshotOptions: argParser.options.containsKey(FlutterOptions.kExtraGenSnapshotOptions)
-        ? stringsArg(FlutterOptions.kExtraGenSnapshotOptions)
+      extraGenSnapshotOptions: extraGenSnapshotOptions?.isNotEmpty ?? false
+        ? extraGenSnapshotOptions
         : null,
       fileSystemRoots: argParser.options.containsKey(FlutterOptions.kFileSystemRoot)
           ? stringsArg(FlutterOptions.kFileSystemRoot)
@@ -600,6 +609,7 @@ abstract class FlutterCommand extends Command<void> {
       dartDefines: argParser.options.containsKey(FlutterOptions.kDartDefinesOption)
           ? stringsArg(FlutterOptions.kDartDefinesOption)
           : const <String>[],
+      dartExperiments: experiments,
     );
   }
 

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

@@ -28,6 +28,7 @@ Future<void> buildWeb(
   BuildInfo buildInfo,
   bool initializePlatform,
   bool csp,
+  List<String> experiments,
 ) async {
   if (!flutterProject.web.existsSync()) {
     throwToolExit('Missing index.html.');
@@ -52,6 +53,8 @@ Future<void> buildWeb(
         kDartDefines: buildInfo.dartDefines.join(','),
         kCspMode: csp.toString(),
         kIconTreeShakerFlag: buildInfo.treeShakeIcons.toString(),
+        if (experiments.isNotEmpty)
+          kEnableExperiment: experiments?.join(','),
       },
       artifacts: globals.artifacts,
       fileSystem: globals.fs,

packages/flutter_tools/test/commands.shard/hermetic/build_macos_test.dart

@@ -249,14 +249,14 @@ void main() {
   });
 
   testUsingContext('hidden when not enabled on macOS host', () {
-    expect(BuildMacosCommand().hidden, true);
+    expect(BuildMacosCommand(verboseHelp: false).hidden, true);
   }, overrides: <Type, Generator>{
     FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: false),
     Platform: () => macosPlatform,
   });
 
   testUsingContext('Not hidden when enabled and on macOS host', () {
-    expect(BuildMacosCommand().hidden, false);
+    expect(BuildMacosCommand(verboseHelp: false).hidden, false);
   }, overrides: <Type, Generator>{
     FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: true),
     Platform: () => macosPlatform,

packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart

@@ -59,6 +59,7 @@ void main() {
       BuildInfo.debug,
       false,
       false,
+      <String>[],
     ), throwsToolExit());
   }, overrides: <Type, Generator>{
     Platform: () => fakePlatform,
@@ -186,7 +187,7 @@ class UrlLauncherPlugin {}
   });
 
   testUsingContext('hidden if feature flag is not enabled', () async {
-    expect(BuildWebCommand().hidden, true);
+    expect(BuildWebCommand(verboseHelp: false).hidden, true);
   }, overrides: <Type, Generator>{
     Platform: () => fakePlatform,
     FileSystem: () => fileSystem,
@@ -196,7 +197,7 @@ class UrlLauncherPlugin {}
   });
 
   testUsingContext('not hidden if feature flag is enabled', () async {
-    expect(BuildWebCommand().hidden, false);
+    expect(BuildWebCommand(verboseHelp: false).hidden, false);
   }, overrides: <Type, Generator>{
     Platform: () => fakePlatform,
     FileSystem: () => fileSystem,

packages/flutter_tools/test/general.shard/build_system/targets/web_test.dart

@@ -229,7 +229,8 @@ void main() {
         ...kDart2jsLinuxArgs,
         '-o',
         environment.buildDir.childFile('app.dill').absolute.path,
-         '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '-Ddart.vm.profile=true',
         '--cfe-only',
         environment.buildDir.childFile('main.dart').absolute.path,
       ]
@@ -253,6 +254,39 @@ void main() {
   }));
 
 
+  test('Dart2JSTarget calls dart2js with expected args with enabled experiment', () => testbed.run(() async {
+    environment.defines[kBuildMode] = 'profile';
+    environment.defines[kEnableExperiment] = 'non-nullable';
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ...kDart2jsLinuxArgs,
+        '--enable-experiment=non-nullable',
+        '-o',
+        environment.buildDir.childFile('app.dill').absolute.path,
+        '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '-Ddart.vm.profile=true',
+        '--cfe-only',
+        environment.buildDir.childFile('main.dart').absolute.path,
+      ]
+    ));
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ...kDart2jsLinuxArgs,
+        '--enable-experiment=non-nullable',
+        '-O4',
+        '-Ddart.vm.profile=true',
+        '--no-minify',
+        '-o',
+        environment.buildDir.childFile('main.dart.js').absolute.path,
+        environment.buildDir.childFile('app.dill').absolute.path,
+      ]
+    ));
+
+    await const Dart2JSTarget().build(environment);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => processManager,
+  }));
+
   test('Dart2JSTarget calls dart2js with expected args in profile mode', () => testbed.run(() async {
     environment.defines[kBuildMode] = 'profile';
     processManager.addCommand(FakeCommand(
@@ -260,7 +294,8 @@ void main() {
         ...kDart2jsLinuxArgs,
         '-o',
         environment.buildDir.childFile('app.dill').absolute.path,
-         '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '-Ddart.vm.profile=true',
         '--cfe-only',
         environment.buildDir.childFile('main.dart').absolute.path,
       ]
@@ -289,7 +324,8 @@ void main() {
         ...kDart2jsLinuxArgs,
         '-o',
         environment.buildDir.childFile('app.dill').absolute.path,
-         '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '-Ddart.vm.product=true',
         '--cfe-only',
         environment.buildDir.childFile('main.dart').absolute.path,
       ]
@@ -318,7 +354,8 @@ void main() {
         ...kDart2jsLinuxArgs,
         '-o',
         environment.buildDir.childFile('app.dill').absolute.path,
-         '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '-Ddart.vm.product=true',
         '--cfe-only',
         environment.buildDir.childFile('main.dart').absolute.path,
       ]
@@ -366,10 +403,11 @@ void main() {
         ...kDart2jsLinuxArgs,
         '-o',
         environment.buildDir.childFile('app.dill').absolute.path,
+        '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '-Ddart.vm.product=true',
         '-DFOO=bar',
         '-DBAZ=qux',
-         '--packages=${globals.fs.path.join('foo', '.packages')}',
-        '--cfe-only',
+       '--cfe-only',
         environment.buildDir.childFile('main.dart').absolute.path,
       ]
     ));
@@ -399,9 +437,10 @@ void main() {
         ...kDart2jsLinuxArgs,
         '-o',
         environment.buildDir.childFile('app.dill').absolute.path,
+        '--packages=${globals.fs.path.join('foo', '.packages')}',
+        '-Ddart.vm.profile=true',
         '-DFOO=bar',
         '-DBAZ=qux',
-         '--packages=${globals.fs.path.join('foo', '.packages')}',
         '--cfe-only',
         environment.buildDir.childFile('main.dart').absolute.path,
       ]