[flutter_tools] Deferred components build system (#76192)

ee417827 · Gary Qian · GitHub · faabc9ab · ee417827 · ee417827
Unverified Commit ee417827 authored Mar 05, 2021 by Gary Qian Committed by GitHub Mar 05, 2021
33 changed files
--- a/dev/bots/test.dart
+++ b/dev/bots/test.dart
@@ -519,7 +519,7 @@ Future<void> _flutterBuild(
    final File file = File(path.join(flutterRoot, relativePathToApplication, 'perf.json'));
    if (!_allTargetsCached(file)) {
      print('${red}Not all build targets cached after second run.$reset');
-      print('The target performance data was: ${file.readAsStringSync()}');
+      print('The target performance data was: ${file.readAsStringSync().replaceAll('},', '},\n')}');
      exit(1);
    }
  }

--- a/packages/flutter_tools/gradle/flutter.gradle
+++ b/packages/flutter_tools/gradle/flutter.gradle
@@ -134,6 +134,14 @@ class FlutterPlugin implements Plugin<Project> {
                }
            }
        }
+
+        if (project.hasProperty('deferred-component-names')) {
+            String[] componentNames = project.property('deferred-component-names').split(',').collect {":${it}"}
+            project.android {
+                dynamicFeatures = componentNames
+            }
+        }
+
        getTargetPlatforms().each { targetArch ->
            String abiValue = PLATFORM_ARCH_MAP[targetArch]
            project.android {
@@ -173,6 +181,11 @@ class FlutterPlugin implements Plugin<Project> {
                    matchingFallbacks = ["debug", "release"]
                }
            }
+            // TODO(garyq): Shrinking is only false for multi apk split aot builds, where shrinking is not allowed yet.
+            // This limitation has been removed experimentally in gradle plugin version 4.2, so we can remove
+            // this check when we upgrade to 4.2+ gradle. Currently, deferred components apps may see
+            // increased app size due to this.
+            if (shouldShrinkResources(project)) {
                release {
                    // Enables code shrinking, obfuscation, and optimization for only
                    // your project's release build type.
@@ -186,6 +199,7 @@ class FlutterPlugin implements Plugin<Project> {
                    proguardFiles project.android.getDefaultProguardFile("proguard-android.txt"), flutterProguardRules, "proguard-rules.pro"
                }
            }
+        }

        if (useLocalEngine()) {
            // This is required to pass the local engine to flutter build aot.
@@ -200,6 +214,13 @@ class FlutterPlugin implements Plugin<Project> {
        project.android.buildTypes.all this.&addFlutterDependencies
    }

+    private static Boolean shouldShrinkResources(Project project) { 
+        if (project.hasProperty("shrink")) {
+            return project.property("shrink").toBoolean()
+        }
+        return true
+    }
+
    /**
     * Adds the dependencies required by the Flutter project.
     * This includes:
@@ -706,6 +727,14 @@ class FlutterPlugin implements Plugin<Project> {
        if (project.hasProperty('code-size-directory')) {
            codeSizeDirectoryValue = project.property('code-size-directory')
        }
+        Boolean deferredComponentsValue = false
+        if (project.hasProperty('deferred-components')) {
+            deferredComponentsValue = project.property('deferred-components').toBoolean()
+        }
+        Boolean validateDeferredComponentsValue = true
+        if (project.hasProperty('validate-deferred-components')) {
+            validateDeferredComponentsValue = project.property('validate-deferred-components').toBoolean()
+        }
        def targetPlatforms = getTargetPlatforms()
        def addFlutterDeps = { variant ->
            if (shouldSplitPerAbi()) {
@@ -747,6 +776,8 @@ class FlutterPlugin implements Plugin<Project> {
                bundleSkSLPath bundleSkSLPathValue
                performanceMeasurementFile performanceMeasurementFileValue
                codeSizeDirectory codeSizeDirectoryValue
+                deferredComponents deferredComponentsValue
+                validateDeferredComponents validateDeferredComponentsValue
                doLast {
                    project.exec {
                        if (Os.isFamily(Os.FAMILY_WINDOWS)) {
@@ -810,7 +841,8 @@ class FlutterPlugin implements Plugin<Project> {
                processResources.dependsOn(copyFlutterAssetsTask)
            }
            return copyFlutterAssetsTask
-        }
+        } // end def addFlutterDeps
+        
        if (isFlutterAppProject()) {
            project.android.applicationVariants.all { variant ->
                Task assembleTask = getAssembleTask(variant)
@@ -883,7 +915,7 @@ class FlutterPlugin implements Plugin<Project> {
                    // | ----------------- | ----------------------------- |
                    // |   Build Variant   |   Flutter Equivalent Variant  |
                    // | ----------------- | ----------------------------- |
-                    // |   freeRelease     |   relese                      |
+                    // |   freeRelease     |   release                      |
                    // |   freeDebug       |   debug                       |
                    // |   freeDevelop     |   debug                       |
                    // |   profile         |   profile                     |
@@ -961,6 +993,10 @@ abstract class BaseFlutterTask extends DefaultTask {
    @Optional @Input
    String codeSizeDirectory;
    String performanceMeasurementFile;
+    @Optional @Input
+    Boolean deferredComponents
+    @Optional @Input
+    Boolean validateDeferredComponents

    @OutputFiles
    FileCollection getDependenciesFiles() {
@@ -985,6 +1021,8 @@ abstract class BaseFlutterTask extends DefaultTask {
        String[] ruleNames;
        if (buildMode == "debug") {
            ruleNames = ["debug_android_application"]
+        } else if (deferredComponents) {
+            ruleNames = targetPlatformValues.collect { "android_aot_deferred_components_bundle_${buildMode}_$it" }
        } else {
            ruleNames = targetPlatformValues.collect { "android_aot_bundle_${buildMode}_$it" }
        }

--- a/packages/flutter_tools/lib/src/android/android_builder.dart
+++ b/packages/flutter_tools/lib/src/android/android_builder.dart
@@ -38,5 +38,7 @@ abstract class AndroidBuilder {
    @required FlutterProject project,
    @required AndroidBuildInfo androidBuildInfo,
    @required String target,
+    bool validateDeferredComponents = true,
+    bool deferredComponentsEnabled = false,
  });
 }
--- 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
@@ -30,10 +30,17 @@ class DeferredComponentsGenSnapshotValidator 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.
-  DeferredComponentsGenSnapshotValidator(Environment env, {
+  DeferredComponentsGenSnapshotValidator(this.env, {
    bool exitOnFail = true,
    String title,
-  }) : super(env, exitOnFail: exitOnFail, title: title);
+  }) : super(env.projectDir, env.logger, exitOnFail: exitOnFail, title: title);
+
+  /// The build environment that should be used to find the input files to run
+  /// checks against.
+  ///
+  /// The checks in this class are meant to be used as part of a build process,
+  /// so an environment should be available.
+  final Environment env;

  // The key used to identify the metadata element as the loading unit id to
  // deferred component mapping.
@@ -58,8 +65,8 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
  /// Where loading unit 2 is included in componentA, loading unit 3 is included
  /// in componentB, and loading unit 4 is included in componentC.
  bool checkAppAndroidManifestComponentLoadingUnitMapping(List<DeferredComponent> components, List<LoadingUnit> generatedLoadingUnits) {
-    final Directory androidDir = env.projectDir.childDirectory('android');
-    inputs.add(env.projectDir.childFile('pubspec.yaml'));
+    final Directory androidDir = projectDir.childDirectory('android');
+    inputs.add(projectDir.childFile('pubspec.yaml'));

    // We do not use the Xml package to handle the writing, as we do not want to
    // erase any user applied formatting and comments. The changes can be
@@ -106,8 +113,10 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
      mappingBuffer.write('$key:${mapping[key]},');
    }
    String encodedMapping = mappingBuffer.toString();
-    // remove trailing comma.
+    // remove trailing comma if any
+    if (encodedMapping.endsWith(',')) {
      encodedMapping = encodedMapping.substring(0, encodedMapping.length - 1);
+    }
    // Check for existing metadata entry and see if needs changes.
    bool exists = false;
    bool modified = false;
@@ -163,7 +172,7 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
  /// considered new.
  bool checkAgainstLoadingUnitsCache(
      List<LoadingUnit> generatedLoadingUnits) {
-    final List<LoadingUnit> cachedLoadingUnits = _parseLodingUnitsCache(env.projectDir.childFile(DeferredComponentsValidator.kLoadingUnitsCacheFileName));
+    final List<LoadingUnit> cachedLoadingUnits = _parseLodingUnitsCache(projectDir.childFile(DeferredComponentsValidator.kLoadingUnitsCacheFileName));
    loadingUnitComparisonResults = <String, dynamic>{};
    final Set<LoadingUnit> unmatchedLoadingUnits = <LoadingUnit>{};
    final List<LoadingUnit> newLoadingUnits = <LoadingUnit>[];
@@ -276,7 +285,7 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
  /// deferred components.
  void writeLoadingUnitsCache(List<LoadingUnit> generatedLoadingUnits) {
    generatedLoadingUnits ??= <LoadingUnit>[];
-    final File cacheFile = env.projectDir.childFile(DeferredComponentsValidator.kLoadingUnitsCacheFileName);
+    final File cacheFile = projectDir.childFile(DeferredComponentsValidator.kLoadingUnitsCacheFileName);
    outputs.add(cacheFile);
    ErrorHandlingFileSystem.deleteIfExists(cacheFile);
    cacheFile.createSync(recursive: true);

--- a/packages/flutter_tools/lib/src/android/deferred_components_prebuild_validator.dart
+++ b/packages/flutter_tools/lib/src/android/deferred_components_prebuild_validator.dart
@@ -10,7 +10,7 @@ import 'package:xml/xml.dart';
 import '../base/deferred_component.dart';
 import '../base/error_handling_io.dart';
 import '../base/file_system.dart';
-import '../build_system/build_system.dart';
+import '../base/logger.dart';
 import '../globals.dart' as globals;
 import '../project.dart';
 import '../template.dart';
@@ -25,20 +25,18 @@ import 'deferred_components_validator.dart';
 class DeferredComponentsPrebuildValidator extends DeferredComponentsValidator {
  /// Constructs a validator instance.
  ///
-  /// The [env] property is used to locate the project files that are checked.
-  ///
  /// The [templatesDir] parameter is optional. If null, the tool's default
  /// templates directory will be used.
  ///
  /// 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(Environment env, {
+  DeferredComponentsPrebuildValidator(Directory projectDir, Logger logger, {
    bool exitOnFail = true,
    String title,
    Directory templatesDir,
  }) : _templatesDir = templatesDir,
-       super(env, exitOnFail: exitOnFail, title: title);
+       super(projectDir, logger, exitOnFail: exitOnFail, title: title);

  final Directory _templatesDir;

@@ -56,7 +54,7 @@ class DeferredComponentsPrebuildValidator extends DeferredComponentsValidator {
  /// This method does not check if the contents of either of the files are
  /// valid, as there are many ways that they can be validly configured.
  Future<bool> checkAndroidDynamicFeature(List<DeferredComponent> components) async {
-    inputs.add(env.projectDir.childFile('pubspec.yaml'));
+    inputs.add(projectDir.childFile('pubspec.yaml'));
    if (components == null || components.isEmpty) {
      return false;
    }
@@ -64,7 +62,8 @@ class DeferredComponentsPrebuildValidator extends DeferredComponentsValidator {
    for (final DeferredComponent component in components) {
      final _DeferredComponentAndroidFiles androidFiles = _DeferredComponentAndroidFiles(
        name: component.name,
-        env: env,
+        projectDir: projectDir,
+        logger: logger,
        templatesDir: _templatesDir
      );
      if (!androidFiles.verifyFilesExist()) {
@@ -106,8 +105,8 @@ class DeferredComponentsPrebuildValidator extends DeferredComponentsValidator {
  /// The string element's name attribute should be the component name with
  /// `Name` as a suffix, and the text contents should be the component name.
  bool checkAndroidResourcesStrings(List<DeferredComponent> components) {
-    final Directory androidDir = env.projectDir.childDirectory('android');
-    inputs.add(env.projectDir.childFile('pubspec.yaml'));
+    final Directory androidDir = projectDir.childDirectory('android');
+    inputs.add(projectDir.childFile('pubspec.yaml'));

    // Add component name mapping to strings.xml
    final File stringRes = androidDir
@@ -202,7 +201,7 @@ class DeferredComponentsPrebuildValidator extends DeferredComponentsValidator {

  /// Deletes all files inside of the validator's output directory.
  void clearOutputDir() {
-    final Directory dir = env.projectDir.childDirectory('build').childDirectory(DeferredComponentsValidator.kDeferredComponentsTempDirectory);
+    final Directory dir = projectDir.childDirectory('build').childDirectory(DeferredComponentsValidator.kDeferredComponentsTempDirectory);
    ErrorHandlingFileSystem.deleteIfExists(dir, recursive: true);
  }
 }
@@ -212,16 +211,18 @@ class DeferredComponentsPrebuildValidator extends DeferredComponentsValidator {
 class _DeferredComponentAndroidFiles {
  _DeferredComponentAndroidFiles({
    @required this.name,
-    @required this.env,
+    @required this.projectDir,
+    this.logger,
    Directory templatesDir,
  }) : _templatesDir = templatesDir;

  // The name of the deferred component.
  final String name;
-  final Environment env;
+  final Directory projectDir;
+  final Logger logger;
  final Directory _templatesDir;

-  Directory get androidDir => env.projectDir.childDirectory('android');
+  Directory get androidDir => projectDir.childDirectory('android');
  Directory get componentDir => androidDir.childDirectory(name);

  File get androidManifestFile => componentDir.childDirectory('src').childDirectory('main').childFile('AndroidManifest.xml');
@@ -250,18 +251,18 @@ class _DeferredComponentAndroidFiles {
  Future<List<File>> _setupComponentFiles(Directory outputDir) async {
    Template template;
    if (_templatesDir != null) {
-      final Directory templateComponentDir = _templatesDir.childDirectory('module${env.fileSystem.path.separator}android${env.fileSystem.path.separator}deferred_component');
+      final Directory templateComponentDir = _templatesDir.childDirectory('module${globals.fs.path.separator}android${globals.fs.path.separator}deferred_component');
      template = Template(templateComponentDir, templateComponentDir, _templatesDir,
-        fileSystem: env.fileSystem,
+        fileSystem: globals.fs,
        templateManifest: null,
-        logger: env.logger,
+        logger: logger,
        templateRenderer: globals.templateRenderer,
      );
    } else {
-      template = await Template.fromName('module${env.fileSystem.path.separator}android${env.fileSystem.path.separator}deferred_component',
-        fileSystem: env.fileSystem,
+      template = await Template.fromName('module${globals.fs.path.separator}android${globals.fs.path.separator}deferred_component',
+        fileSystem: globals.fs,
        templateManifest: null,
-        logger: env.logger,
+        logger: logger,
        templateRenderer: globals.templateRenderer,
      );
    }

--- a/packages/flutter_tools/lib/src/android/deferred_components_validator.dart
+++ b/packages/flutter_tools/lib/src/android/deferred_components_validator.dart
@@ -7,8 +7,8 @@
 import '../base/common.dart';
 import '../base/deferred_component.dart';
 import '../base/file_system.dart';
+import '../base/logger.dart';
 import '../base/terminal.dart';
-import '../build_system/build_system.dart';
 import '../globals.dart' as globals;

 /// A class to configure and run deferred component setup verification checks
@@ -21,10 +21,10 @@ 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.env, {
+  DeferredComponentsValidator(this.projectDir, this.logger, {
    this.exitOnFail = true,
    String title,
-  }) : outputDir = env.projectDir
+  }) : outputDir = projectDir
        .childDirectory('build')
        .childDirectory(kDeferredComponentsTempDirectory),
      inputs = <File>[],
@@ -34,12 +34,9 @@ abstract class DeferredComponentsValidator {
      modifiedFiles = <String>[],
      invalidFiles = <String, String>{},
      diffLines = <String>[];
-  /// The build environment that should be used to find the input files to run
-  /// checks against.
-  ///
-  /// The checks in this class are meant to be used as part of a build process,
-  /// so an environment should be available.
-  final Environment env;
+
+  /// Logger to use for [displayResults] output.
+  final Logger logger;

  /// When true, failed checks and tasks will result in [attemptToolExit]
  /// triggering [throwToolExit].
@@ -54,6 +51,9 @@ abstract class DeferredComponentsValidator {
  /// The title printed at the top of the results of [displayResults]
  final String title;

+  /// The root directory of the flutter project.
+  final Directory projectDir;
+
  /// The temporary directory that the validator writes recommended files into.
  final Directory outputDir;

@@ -111,20 +111,20 @@ abstract class DeferredComponentsValidator {
  /// All checks that are desired should be run before calling this method.
  void displayResults() {
    if (changesNeeded) {
-      env.logger.printStatus(_thickDivider);
-      env.logger.printStatus(title, indent: (_thickDivider.length - title.length) ~/ 2, emphasis: true);
-      env.logger.printStatus(_thickDivider);
+      logger.printStatus(_thickDivider);
+      logger.printStatus(title, indent: (_thickDivider.length - title.length) ~/ 2, emphasis: true);
+      logger.printStatus(_thickDivider);
      // Log any file reading/existence errors.
      if (invalidFiles.isNotEmpty) {
-        env.logger.printStatus('Errors checking the following files:\n', emphasis: true);
+        logger.printStatus('Errors checking the following files:\n', emphasis: true);
        for (final String key in invalidFiles.keys) {
-          env.logger.printStatus('  - $key: ${invalidFiles[key]}\n');
+          logger.printStatus('  - $key: ${invalidFiles[key]}\n');
        }
      }
      // Log diff file contents, with color highlighting
      if (diffLines != null && diffLines.isNotEmpty) {
-        env.logger.printStatus('Diff between `android` and expected files:', emphasis: true);
-        env.logger.printStatus('');
+        logger.printStatus('Diff between `android` and expected files:', emphasis: true);
+        logger.printStatus('');
        for (final String line in diffLines) {
          // We only care about diffs in files that have
          // counterparts.
@@ -137,62 +137,62 @@ abstract class DeferredComponentsValidator {
          } else if (line.startsWith('-')) {
            color = TerminalColor.red;
          }
-          env.logger.printStatus(line, color: color);
+          logger.printStatus(line, color: color);
        }
-        env.logger.printStatus('');
+        logger.printStatus('');
      }
      // Log any newly generated and modified files.
      if (generatedFiles.isNotEmpty) {
-        env.logger.printStatus('Newly generated android files:', emphasis: true);
+        logger.printStatus('Newly generated android files:', emphasis: true);
        for (final String filePath in generatedFiles) {
-          final String shortenedPath = filePath.substring(env.projectDir.parent.path.length + 1);
-          env.logger.printStatus('  - $shortenedPath', color: TerminalColor.grey);
+          final String shortenedPath = filePath.substring(projectDir.parent.path.length + 1);
+          logger.printStatus('  - $shortenedPath', color: TerminalColor.grey);
        }
-        env.logger.printStatus('');
+        logger.printStatus('');
      }
      if (modifiedFiles.isNotEmpty) {
-        env.logger.printStatus('Modified android files:', emphasis: true);
+        logger.printStatus('Modified android files:', emphasis: true);
        for (final String filePath in modifiedFiles) {
-          final String shortenedPath = filePath.substring(env.projectDir.parent.path.length + 1);
-          env.logger.printStatus('  - $shortenedPath', color: TerminalColor.grey);
+          final String shortenedPath = filePath.substring(projectDir.parent.path.length + 1);
+          logger.printStatus('  - $shortenedPath', color: TerminalColor.grey);
        }
-        env.logger.printStatus('');
+        logger.printStatus('');
      }
      if (generatedFiles.isNotEmpty || modifiedFiles.isNotEmpty) {
-        env.logger.printStatus('''
+        logger.printStatus('''
 The above files have been placed into `build/$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) {
-          env.logger.printStatus(r'''
+          logger.printStatus(r'''

 The recommended changes can be quickly applied by running:

  $ patch -p0 < build/setup_deferred_components.diff
 ''');
        }
-        env.logger.printStatus('$_thinDivider\n');
+        logger.printStatus('$_thinDivider\n');
      }
      // Log loading unit golden changes, if any.
      if (loadingUnitComparisonResults != null) {
        if ((loadingUnitComparisonResults['new'] as List<LoadingUnit>).isNotEmpty) {
-          env.logger.printStatus('New loading units were found:', emphasis: true);
+          logger.printStatus('New loading units were found:', emphasis: true);
          for (final LoadingUnit unit in loadingUnitComparisonResults['new'] as List<LoadingUnit>) {
-            env.logger.printStatus(unit.toString(), color: TerminalColor.grey, indent: 2);
+            logger.printStatus(unit.toString(), color: TerminalColor.grey, indent: 2);
          }
-          env.logger.printStatus('');
+          logger.printStatus('');
        }
        if ((loadingUnitComparisonResults['missing'] as Set<LoadingUnit>).isNotEmpty) {
-          env.logger.printStatus('Previously existing loading units no longer exist:', emphasis: true);
+          logger.printStatus('Previously existing loading units no longer exist:', emphasis: true);
          for (final LoadingUnit unit in loadingUnitComparisonResults['missing'] as Set<LoadingUnit>) {
-            env.logger.printStatus(unit.toString(), color: TerminalColor.grey, indent: 2);
+            logger.printStatus(unit.toString(), color: TerminalColor.grey, indent: 2);
          }
-          env.logger.printStatus('');
+          logger.printStatus('');
        }
        if (loadingUnitComparisonResults['match'] as bool) {
-          env.logger.printStatus('No change in generated loading units.\n');
+          logger.printStatus('No change in generated loading units.\n');
        } else {
-          env.logger.printStatus('''
+          logger.printStatus('''
 It is recommended to verify that the changed loading units are expected
 and to update the `deferred-components` section in `pubspec.yaml` to
 incorporate any changes. The full list of generated loading units can be
@@ -205,14 +205,14 @@ $_thinDivider\n''');
        }
      }
      // TODO(garyq): Add link to web tutorial/guide once it is written.
-      env.logger.printStatus('''
-Setup verification can be skipped by passing the `--no-verify-deferred-components`
+      logger.printStatus('''
+Setup verification can be skipped by passing the `--no-validate-deferred-components`
 flag, however, doing so may put your app at risk of not functioning even if the
 build is successful.
 $_thickDivider''');
      return;
    }
-    env.logger.printStatus('$title passed.');
+    logger.printStatus('$title passed.');
  }

  void attemptToolExit() {

--- a/packages/flutter_tools/lib/src/android/gradle.dart
+++ b/packages/flutter_tools/lib/src/android/gradle.dart
@@ -12,6 +12,7 @@ import 'package:xml/xml.dart';
 import '../artifacts.dart';
 import '../base/analyze_size.dart';
 import '../base/common.dart';
+import '../base/deferred_component.dart';
 import '../base/file_system.dart';
 import '../base/io.dart';
 import '../base/logger.dart';
@@ -242,6 +243,8 @@ class AndroidGradleBuilder implements AndroidBuilder {
    @required FlutterProject project,
    @required AndroidBuildInfo androidBuildInfo,
    @required String target,
+    bool validateDeferredComponents = true,
+    bool deferredComponentsEnabled = false,
  }) async {
    await buildGradleApp(
      project: project,
@@ -249,6 +252,8 @@ class AndroidGradleBuilder implements AndroidBuilder {
      target: target,
      isBuildingBundle: true,
      localGradleErrors: gradleErrors,
+      validateDeferredComponents: validateDeferredComponents,
+      deferredComponentsEnabled: deferredComponentsEnabled,
    );
  }

@@ -270,6 +275,8 @@ class AndroidGradleBuilder implements AndroidBuilder {
    @required bool isBuildingBundle,
    @required List<GradleHandledError> localGradleErrors,
    bool shouldBuildPluginAsAar = false,
+    bool validateDeferredComponents = true,
+    bool deferredComponentsEnabled = false,
    int retries = 1,
  }) async {
    assert(project != null);
@@ -355,8 +362,29 @@ class AndroidGradleBuilder implements AndroidBuilder {
    if (target != null) {
      command.add('-Ptarget=$target');
    }
+    if (project.manifest.deferredComponents != null) {
+      if (deferredComponentsEnabled) {
+        command.add('-Pdeferred-components=true');
+        androidBuildInfo.buildInfo.dartDefines.add('validate-deferred-components=$validateDeferredComponents');
+      }
+      // Pass in deferred components regardless of building split aot to satisfy
+      // android dynamic features registry in build.gradle.
+      final List<String> componentNames = <String>[];
+      for (final DeferredComponent component in project.manifest.deferredComponents) {
+        componentNames.add(component.name);
+      }
+      if (componentNames.isNotEmpty) {
+        command.add('-Pdeferred-component-names=${componentNames.join(',')}');
+        // Multi-apk applications cannot use shrinking. This is only relevant when using
+        // android dynamic feature modules.
+        _logger.printStatus(
+          'Shrinking has been disabled for this build due to deferred components. Shrinking is '
+          'not available for multi-apk applications. This limitation is expected to be removed '
+          'when Gradle plugin 4.2+ is available in Flutter.', color: TerminalColor.yellow);
+        command.add('-Pshrink=false');
+      }
+    }
    command.addAll(androidBuildInfo.buildInfo.toGradleConfig());
-
    if (buildInfo.fileSystemRoots != null && buildInfo.fileSystemRoots.isNotEmpty) {
      command.add('-Pfilesystem-roots=${buildInfo.fileSystemRoots.join('|')}');
    }

--- a/packages/flutter_tools/lib/src/asset.dart
+++ b/packages/flutter_tools/lib/src/asset.dart
@@ -8,6 +8,7 @@ import 'package:meta/meta.dart';
 import 'package:package_config/package_config.dart';

 import 'base/context.dart';
+import 'base/deferred_component.dart';
 import 'base/file_system.dart';
 import 'base/logger.dart';
 import 'base/platform.dart';
@@ -53,7 +54,8 @@ abstract class AssetBundleFactory {
    @required Logger logger,
    @required FileSystem fileSystem,
    @required Platform platform,
-  }) => _ManifestAssetBundleFactory(logger: logger, fileSystem: fileSystem, platform: platform);
+    bool splitDeferredAssets = false,
+  }) => _ManifestAssetBundleFactory(logger: logger, fileSystem: fileSystem, platform: platform, splitDeferredAssets: splitDeferredAssets);

  /// Creates a new [AssetBundle].
  AssetBundle createBundle();
@@ -62,6 +64,10 @@ abstract class AssetBundleFactory {
 abstract class AssetBundle {
  Map<String, DevFSContent> get entries;

+  /// The files that were specified under the deferred components assets sections
+  /// in pubspec.
+  Map<String, Map<String, DevFSContent>> get deferredComponentsEntries;
+
  /// Additional files that this bundle depends on that are not included in the
  /// output result.
  List<File> get additionalDependencies;
@@ -75,6 +81,7 @@ abstract class AssetBundle {
    String manifestPath = defaultManifestPath,
    String assetDirPath,
    @required String packagesPath,
+    bool deferredComponentsEnabled = false,
  });
 }

@@ -83,16 +90,19 @@ class _ManifestAssetBundleFactory implements AssetBundleFactory {
    @required Logger logger,
    @required FileSystem fileSystem,
    @required Platform platform,
+    bool splitDeferredAssets = false,
  }) : _logger = logger,
       _fileSystem = fileSystem,
-       _platform = platform;
+       _platform = platform,
+       _splitDeferredAssets = splitDeferredAssets;

  final Logger _logger;
  final FileSystem _fileSystem;
  final Platform _platform;
+  final bool _splitDeferredAssets;

  @override
-  AssetBundle createBundle() => ManifestAssetBundle(logger: _logger, fileSystem: _fileSystem, platform: _platform);
+  AssetBundle createBundle() => ManifestAssetBundle(logger: _logger, fileSystem: _fileSystem, platform: _platform, splitDeferredAssets: _splitDeferredAssets);
 }

 /// An asset bundle based on a pubspec.yaml file.
@@ -103,19 +113,25 @@ class ManifestAssetBundle implements AssetBundle {
    @required Logger logger,
    @required FileSystem fileSystem,
    @required Platform platform,
+    bool splitDeferredAssets = false,
  }) : _logger = logger,
       _fileSystem = fileSystem,
       _platform = platform,
+       _splitDeferredAssets = splitDeferredAssets,
       _licenseCollector = LicenseCollector(fileSystem: fileSystem);

  final Logger _logger;
  final FileSystem _fileSystem;
  final LicenseCollector _licenseCollector;
  final Platform _platform;
+  final bool _splitDeferredAssets;

  @override
  final Map<String, DevFSContent> entries = <String, DevFSContent>{};

+  @override
+  final Map<String, Map<String, DevFSContent>> deferredComponentsEntries = <String, Map<String, DevFSContent>>{};
+
  // If an asset corresponds to a wildcard directory, then it may have been
  // updated without changes to the manifest. These are only tracked for
  // the current project.
@@ -163,6 +179,7 @@ class ManifestAssetBundle implements AssetBundle {
    String manifestPath = defaultManifestPath,
    String assetDirPath,
    @required String packagesPath,
+    bool deferredComponentsEnabled = false,
  }) async {
    assetDirPath ??= getAssetBuildDirectory();
    FlutterProject flutterProject;
@@ -197,12 +214,7 @@ class ManifestAssetBundle implements AssetBundle {
    // in the pubspec.yaml file's assets and font and sections. The
    // value of each image asset is a list of resolution-specific "variants",
    // see _AssetDirectoryCache.
-    final Map<_Asset, List<_Asset>> assetVariants = _parseAssets(
-      packageConfig,
-      flutterManifest,
-      wildcardDirectories,
-      assetBasePath,
-      excludeDirs: <String>[
+    final List<String> excludeDirs = <String>[
      assetDirPath,
      getBuildDirectory(),
      if (flutterProject.ios.existsSync())
@@ -213,13 +225,38 @@ class ManifestAssetBundle implements AssetBundle {
        flutterProject.windows.managedDirectory.path,
      if (flutterProject.linux.existsSync())
        flutterProject.linux.managedDirectory.path,
-      ],
+    ];
+    final Map<_Asset, List<_Asset>> assetVariants = _parseAssets(
+      packageConfig,
+      flutterManifest,
+      wildcardDirectories,
+      assetBasePath,
+      excludeDirs: excludeDirs,
    );

    if (assetVariants == null) {
      return 1;
    }

+    // Parse assets for  deferred components.
+    final Map<String, Map<_Asset, List<_Asset>>> deferredComponentsAssetVariants = _parseDeferredComponentsAssets(
+      flutterManifest,
+      packageConfig,
+      assetBasePath,
+      wildcardDirectories,
+      flutterProject.directory,
+      excludeDirs: excludeDirs,
+    );
+    if (!_splitDeferredAssets || !deferredComponentsEnabled) {
+      // Include the assets in the regular set of assets if not using deferred
+      // components.
+      for (final String componentName in deferredComponentsAssetVariants.keys) {
+        assetVariants.addAll(deferredComponentsAssetVariants[componentName]);
+      }
+      deferredComponentsAssetVariants.clear();
+      deferredComponentsEntries.clear();
+    }
+
    final bool includesMaterialFonts = flutterManifest.usesMaterialDesign;
    final List<Map<String, dynamic>> fonts = _parseFonts(
      flutterManifest,
@@ -314,6 +351,39 @@ class ManifestAssetBundle implements AssetBundle {
        entries[variant.entryUri.path] ??= DevFSFileContent(variantFile);
      }
    }
+    // Save the contents of each deferred component image, image variant, and font
+    // asset in deferredComponentsEntries.
+    if (deferredComponentsAssetVariants != null) {
+      for (final String componentName in deferredComponentsAssetVariants.keys) {
+        deferredComponentsEntries[componentName] = <String, DevFSContent>{};
+        for (final _Asset asset in deferredComponentsAssetVariants[componentName].keys) {
+          final File assetFile = asset.lookupAssetFile(_fileSystem);
+          if (!assetFile.existsSync() && deferredComponentsAssetVariants[componentName][asset].isEmpty) {
+            _logger.printStatus('Error detected in pubspec.yaml:', emphasis: true);
+            _logger.printError('No file or variants found for $asset.\n');
+            if (asset.package != null) {
+              _logger.printError('This asset was included from package ${asset.package.name}.');
+            }
+            return 1;
+          }
+          // The file name for an asset's "main" entry is whatever appears in
+          // the pubspec.yaml file. The main entry's file must always exist for
+          // font assets. It need not exist for an image if resolution-specific
+          // variant files exist. An image's main entry is treated the same as a
+          // "1x" resolution variant and if both exist then the explicit 1x
+          // variant is preferred.
+          if (assetFile.existsSync()) {
+            assert(!deferredComponentsAssetVariants[componentName][asset].contains(asset));
+            deferredComponentsAssetVariants[componentName][asset].insert(0, asset);
+          }
+          for (final _Asset variant in deferredComponentsAssetVariants[componentName][asset]) {
+            final File variantFile = variant.lookupAssetFile(_fileSystem);
+            assert(variantFile.existsSync());
+            deferredComponentsEntries[componentName][variant.entryUri.path] ??= DevFSFileContent(variantFile);
+          }
+        }
+      }
+    }
    final List<_Asset> materialAssets = <_Asset>[
      if (flutterManifest.usesMaterialDesign)
        ..._getMaterialAssets(),
@@ -410,6 +480,50 @@ class ManifestAssetBundle implements AssetBundle {
    ];
  }

+  Map<String, Map<_Asset, List<_Asset>>> _parseDeferredComponentsAssets(
+    FlutterManifest flutterManifest,
+    PackageConfig packageConfig,
+    String assetBasePath,
+    List<Uri> wildcardDirectories,
+    Directory projectDirectory, {
+    List<String> excludeDirs = const <String>[],
+  }) {
+    final List<DeferredComponent> components = flutterManifest.deferredComponents;
+    final Map<String, Map<_Asset, List<_Asset>>> deferredComponentsAssetVariants = <String, Map<_Asset, List<_Asset>>>{};
+    if (components == null) {
+      return deferredComponentsAssetVariants;
+    }
+    for (final DeferredComponent component in components) {
+      deferredComponentsAssetVariants[component.name] = <_Asset, List<_Asset>>{};
+      final _AssetDirectoryCache cache = _AssetDirectoryCache(<String>[], _fileSystem);
+      for (final Uri assetUri in component.assets) {
+        if (assetUri.path.endsWith('/')) {
+          wildcardDirectories.add(assetUri);
+          _parseAssetsFromFolder(
+            packageConfig,
+            flutterManifest,
+            assetBasePath,
+            cache,
+            deferredComponentsAssetVariants[component.name],
+            assetUri,
+            excludeDirs: excludeDirs,
+          );
+        } else {
+          _parseAssetFromFile(
+            packageConfig,
+            flutterManifest,
+            assetBasePath,
+            cache,
+            deferredComponentsAssetVariants[component.name],
+            assetUri,
+            excludeDirs: excludeDirs,
+          );
+        }
+      }
+    }
+    return deferredComponentsAssetVariants;
+  }
+
  DevFSStringContent _createAssetManifest(Map<_Asset, List<_Asset>> assetVariants) {
    final Map<String, List<String>> jsonObject = <String, List<String>>{};
    final List<_Asset> assets = assetVariants.keys.toList()

--- a/packages/flutter_tools/lib/src/base/terminal.dart
+++ b/packages/flutter_tools/lib/src/base/terminal.dart
@@ -167,7 +167,7 @@ class AnsiTerminal implements Terminal {
  static const String cyan = '\u001b[36m';
  static const String magenta = '\u001b[35m';
  static const String yellow = '\u001b[33m';
-  static const String grey = '\u001b[1;30m';
+  static const String grey = '\u001b[90m';

  static const Map<TerminalColor, String> _colorMap = <TerminalColor, String>{
    TerminalColor.red: red,

--- a/packages/flutter_tools/lib/src/build_system/depfile.dart
+++ b/packages/flutter_tools/lib/src/build_system/depfile.dart
@@ -25,10 +25,12 @@ class DepfileService {

  /// Given an [depfile] File, write the depfile contents.
  ///
-  /// If either [inputs] or [outputs] is empty, ensures the file does not
-  /// exist.
-  void writeToFile(Depfile depfile, File output) {
-    if (depfile.inputs.isEmpty || depfile.outputs.isEmpty) {
+  /// If both [inputs] and [outputs] are empty, ensures the file does not
+  /// exist. This can be overriden with the [writeEmpty] parameter when
+  /// both static and runtime dependencies exist and it is not desired
+  /// to force a rerun due to no depfile.
+  void writeToFile(Depfile depfile, File output, {bool writeEmpty = false}) {
+    if (depfile.inputs.isEmpty && depfile.outputs.isEmpty && !writeEmpty) {
      ErrorHandlingFileSystem.deleteIfExists(output);
      return;
    }

--- a/packages/flutter_tools/lib/src/build_system/source.dart
+++ b/packages/flutter_tools/lib/src/build_system/source.dart
@@ -146,7 +146,7 @@ class SourceVisitor implements ResolvedFiles {
      throw InvalidPatternException(pattern);
    }
    if (!environment.fileSystem.directory(filePath).existsSync()) {
-      throw Exception('$filePath does not exist!');
+      environment.fileSystem.directory(filePath).createSync(recursive: true);
    }
    for (final FileSystemEntity entity in environment.fileSystem.directory(filePath).listSync()) {
      final String filename = environment.fileSystem.path.basename(entity.path);

--- a/packages/flutter_tools/lib/src/build_system/targets/android.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/android.dart
--- a/packages/flutter_tools/lib/src/build_system/targets/assets.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/assets.dart
@@ -34,6 +34,7 @@ const String kBundleSkSLPath = 'BundleSkSLPath';
 Future<Depfile> copyAssets(Environment environment, Directory outputDirectory, {
  Map<String, DevFSContent> additionalContent,
  @required TargetPlatform targetPlatform,
+  BuildMode buildMode,
 }) async {
  // Check for an SkSL bundle.
  final String shaderBundlePath = environment.inputs[kBundleSkSLPath];
@@ -51,11 +52,13 @@ Future<Depfile> copyAssets(Environment environment, Directory outputDirectory, {
    logger: environment.logger,
    fileSystem: environment.fileSystem,
    platform: globals.platform,
+    splitDeferredAssets: buildMode != BuildMode.debug && buildMode != BuildMode.jitRelease,
  ).createBundle();
  final int resultCode = await assetBundle.build(
    manifestPath: pubspecFile.path,
    packagesPath: environment.projectDir.childFile('.packages').path,
    assetDirPath: null,
+    deferredComponentsEnabled: environment.defines[kDeferredComponents] == 'true',
  );
  if (resultCode != 0) {
    throw Exception('Failed to bundle asset files.');
@@ -114,6 +117,56 @@ Future<Depfile> copyAssets(Environment environment, Directory outputDirectory, {
        resource.release();
      }
  }));
+
+  // Copy deferred components assets only for release or profile builds.
+  // The assets are included in assetBundle.entries as a normal asset when
+  // building as debug.
+  if (environment.defines[kDeferredComponents] == 'true') {
+    await Future.wait<void>(
+      assetBundle.deferredComponentsEntries.entries.map<Future<void>>((MapEntry<String, Map<String, DevFSContent>> componentEntries) async {
+        final Directory componentOutputDir =
+            environment.projectDir
+                .childDirectory('build')
+                .childDirectory(componentEntries.key)
+                .childDirectory('intermediates')
+                .childDirectory('flutter');
+        await Future.wait<void>(
+          componentEntries.value.entries.map<Future<void>>((MapEntry<String, DevFSContent> entry) async {
+            final PoolResource resource = await pool.request();
+            try {
+              // This will result in strange looking files, for example files with `/`
+              // on Windows or files that end up getting URI encoded such as `#.ext`
+              // to `%23.ext`. However, we have to keep it this way since the
+              // platform channels in the framework will URI encode these values,
+              // and the native APIs will look for files this way.
+
+              // If deferred components are disabled, then copy assets to regular location.
+              final File file = environment.defines[kDeferredComponents] == 'true'
+                ? environment.fileSystem.file(
+                    environment.fileSystem.path.join(componentOutputDir.path, buildMode.name, 'deferred_assets', 'flutter_assets', entry.key))
+                : environment.fileSystem.file(
+                    environment.fileSystem.path.join(outputDirectory.path, entry.key));
+              outputs.add(file);
+              file.parent.createSync(recursive: true);
+              final DevFSContent content = entry.value;
+              if (content is DevFSFileContent && content.file is File) {
+                inputs.add(content.file as File);
+                if (!await iconTreeShaker.subsetFont(
+                  input: content.file as File,
+                  outputPath: file.path,
+                  relativePath: entry.key,
+                )) {
+                  await (content.file as File).copy(file.path);
+                }
+              } else {
+                await file.writeAsBytes(await entry.value.contentsAsBytes());
+              }
+            } finally {
+              resource.release();
+            }
+        }));
+    }));
+  }
  final Depfile depfile = Depfile(inputs + assetBundle.additionalDependencies, outputs);
  if (shaderBundlePath != null) {
    final File skSLBundleFile = environment.fileSystem

--- a/packages/flutter_tools/lib/src/build_system/targets/common.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/common.dart
@@ -45,9 +45,9 @@ const String kExtraFrontEndOptions = 'ExtraFrontEndOptions';
 /// This is expected to be a comma separated list of strings.
 const String kExtraGenSnapshotOptions = 'ExtraGenSnapshotOptions';

-/// Whether the app should run gen_snapshot as a split aot build for deferred
+/// Whether the build should run gen_snapshot as a split aot build for deferred
 /// components.
-const String kSplitAot = 'SplitAot';
+const String kDeferredComponents = 'DeferredComponents';

 /// Whether to strip source code information out of release builds and where to save it.
 const String kSplitDebugInfo = 'SplitDebugInfo';
@@ -131,6 +131,7 @@ class CopyFlutterBundle extends Target {
      environment,
      environment.outputDir,
      targetPlatform: TargetPlatform.android,
+      buildMode: buildMode,
    );
    final DepfileService depfileService = DepfileService(
      fileSystem: environment.fileSystem,

--- a/packages/flutter_tools/lib/src/build_system/targets/deferred_components.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/deferred_components.dart
@@ -8,25 +8,26 @@ import 'package:meta/meta.dart';

 import '../../android/deferred_components_gen_snapshot_validator.dart';
 import '../../base/deferred_component.dart';
+import '../../build_info.dart';
 import '../../project.dart';
 import '../build_system.dart';
 import '../depfile.dart';
+import 'android.dart';

 /// Creates a [DeferredComponentsGenSnapshotValidator], runs the checks, and displays the validator
 /// output to the developer if changes are recommended.
 class DeferredComponentsGenSnapshotValidatorTarget extends Target {
  /// Create an [AndroidAotDeferredComponentsBundle] implementation for a given [targetPlatform] and [buildMode].
  DeferredComponentsGenSnapshotValidatorTarget({
-    @required this.dependency,
-    @required this.abis,
+    @required this.deferredComponentsDependencies,
+    @required this.nonDeferredComponentsDependencies,
    this.title,
    this.exitOnFail = true,
-    String name = 'deferred_components_setup_validator',
-  }) : _name = name;
+  });

-  /// The [AndroidAotDeferredComponentsBundle] derived target instances this rule depends on packed
-  /// as a [CompositeTarget].
-  final CompositeTarget dependency;
+  /// The [AndroidAotDeferredComponentsBundle] derived target instances this rule depends on.
+  final List<AndroidAotDeferredComponentsBundle> deferredComponentsDependencies;
+  final List<Target> nonDeferredComponentsDependencies;

  /// The title of the [DeferredComponentsGenSnapshotValidator] that is
  /// displayed to the developer when logging results.
@@ -37,11 +38,20 @@ class DeferredComponentsGenSnapshotValidatorTarget extends Target {
  final bool exitOnFail;

  /// The abis to validate.
-  final List<String> abis;
+  List<String> get _abis {
+    final List<String> abis = <String>[];
+    for (final AndroidAotDeferredComponentsBundle target in deferredComponentsDependencies) {
+      if (deferredComponentsTargets.contains(target.name)) {
+        abis.add(
+          getNameForAndroidArch(getAndroidArchForName(getNameForTargetPlatform(target.dependency.targetPlatform)))
+        );
+      }
+    }
+    return abis;
+  }

  @override
-  String get name => _name;
-  final String _name;
+  String get name => 'deferred_components_gen_snapshot_validator';

  @override
  List<Source> get inputs => const <Source>[];
@@ -55,7 +65,11 @@ class DeferredComponentsGenSnapshotValidatorTarget extends Target {
  ];

  @override
-  List<Target> get dependencies => dependency == null ? <Target>[] : <Target>[dependency];
+  List<Target> get dependencies {
+    final List<Target> deps = <Target>[CompositeTarget(deferredComponentsDependencies)];
+    deps.addAll(nonDeferredComponentsDependencies);
+    return deps;
+  }

  @visibleForTesting
  DeferredComponentsGenSnapshotValidator validator;
@@ -75,7 +89,7 @@ class DeferredComponentsGenSnapshotValidatorTarget extends Target {
    final List<LoadingUnit> generatedLoadingUnits = LoadingUnit.parseGeneratedLoadingUnits(
        environment.outputDir,
        environment.logger,
-        abis: abis
+        abis: _abis
    );

    validator

--- a/packages/flutter_tools/lib/src/commands/assemble.dart
+++ b/packages/flutter_tools/lib/src/commands/assemble.dart
@@ -14,6 +14,7 @@ import '../build_system/depfile.dart';
 import '../build_system/targets/android.dart';
 import '../build_system/targets/assets.dart';
 import '../build_system/targets/common.dart';
+import '../build_system/targets/deferred_components.dart';
 import '../build_system/targets/ios.dart';
 import '../build_system/targets/linux.dart';
 import '../build_system/targets/macos.dart';
@@ -27,34 +28,34 @@ import '../reporting/reporting.dart';
 import '../runner/flutter_command.dart';

 /// All currently implemented targets.
-const List<Target> _kDefaultTargets = <Target>[
+List<Target> _kDefaultTargets = <Target>[
  // Shared targets
-  CopyAssets(),
-  KernelSnapshot(),
-  AotElfProfile(TargetPlatform.android_arm),
-  AotElfRelease(TargetPlatform.android_arm),
-  AotAssemblyProfile(),
-  AotAssemblyRelease(),
+  const CopyAssets(),
+  const KernelSnapshot(),
+  const AotElfProfile(TargetPlatform.android_arm),
+  const AotElfRelease(TargetPlatform.android_arm),
+  const AotAssemblyProfile(),
+  const AotAssemblyRelease(),
  // macOS targets
-  DebugMacOSFramework(),
-  DebugMacOSBundleFlutterAssets(),
-  ProfileMacOSBundleFlutterAssets(),
-  ReleaseMacOSBundleFlutterAssets(),
+  const DebugMacOSFramework(),
+  const DebugMacOSBundleFlutterAssets(),
+  const ProfileMacOSBundleFlutterAssets(),
+  const ReleaseMacOSBundleFlutterAssets(),
  // Linux targets
-  DebugBundleLinuxAssets(TargetPlatform.linux_x64),
-  DebugBundleLinuxAssets(TargetPlatform.linux_arm64),
-  ProfileBundleLinuxAssets(TargetPlatform.linux_x64),
-  ProfileBundleLinuxAssets(TargetPlatform.linux_arm64),
-  ReleaseBundleLinuxAssets(TargetPlatform.linux_x64),
-  ReleaseBundleLinuxAssets(TargetPlatform.linux_arm64),
+  const DebugBundleLinuxAssets(TargetPlatform.linux_x64),
+  const DebugBundleLinuxAssets(TargetPlatform.linux_arm64),
+  const ProfileBundleLinuxAssets(TargetPlatform.linux_x64),
+  const ProfileBundleLinuxAssets(TargetPlatform.linux_arm64),
+  const ReleaseBundleLinuxAssets(TargetPlatform.linux_x64),
+  const ReleaseBundleLinuxAssets(TargetPlatform.linux_arm64),
  // Web targets
-  WebServiceWorker(),
-  ReleaseAndroidApplication(),
+  const WebServiceWorker(),
+  const ReleaseAndroidApplication(),
  // This is a one-off rule for bundle and aot compat.
-  CopyFlutterBundle(),
+  const CopyFlutterBundle(),
  // Android targets,
-  DebugAndroidApplication(),
-  ProfileAndroidApplication(),
+  const DebugAndroidApplication(),
+  const ProfileAndroidApplication(),
  // Android ABI specific AOT rules.
  androidArmProfileBundle,
  androidArm64ProfileBundle,
@@ -62,15 +63,22 @@ const List<Target> _kDefaultTargets = <Target>[
  androidArmReleaseBundle,
  androidArm64ReleaseBundle,
  androidx64ReleaseBundle,
+  // Deferred component enabled AOT rules
+  androidArmProfileDeferredComponentsBundle,
+  androidArm64ProfileDeferredComponentsBundle,
+  androidx64ProfileDeferredComponentsBundle,
+  androidArmReleaseDeferredComponentsBundle,
+  androidArm64ReleaseDeferredComponentsBundle,
+  androidx64ReleaseDeferredComponentsBundle,
  // iOS targets
-  DebugIosApplicationBundle(),
-  ProfileIosApplicationBundle(),
-  ReleaseIosApplicationBundle(),
+  const DebugIosApplicationBundle(),
+  const ProfileIosApplicationBundle(),
+  const ReleaseIosApplicationBundle(),
  // Windows targets
-  UnpackWindows(),
-  DebugBundleWindowsAssets(),
-  ProfileBundleWindowsAssets(),
-  ReleaseBundleWindowsAssets(),
+  const UnpackWindows(),
+  const DebugBundleWindowsAssets(),
+  const ProfileBundleWindowsAssets(),
+  const ReleaseBundleWindowsAssets(),
 ];

 // TODO(ianh): https://github.com/dart-lang/args/issues/181 will allow us to remove useLegacyNames
@@ -171,6 +179,24 @@ class AssembleCommand extends FlutterCommand {
    return results;
  }

+  bool isDeferredComponentsTargets() {
+    for (final String targetName in argResults.rest) {
+      if (deferredComponentsTargets.contains(targetName)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool isDebug() {
+    for (final String targetName in argResults.rest) {
+      if (targetName.contains('debug')) {
+        return true;
+      }
+    }
+    return false;
+  }
+
  /// The environmental configuration for a build invocation.
  Environment createEnvironment() {
    final FlutterProject flutterProject = FlutterProject.current();
@@ -221,6 +247,10 @@ class AssembleCommand extends FlutterCommand {
    if (argResults.wasParsed(useLegacyNames ? kDartDefines : FlutterOptions.kDartDefinesOption)) {
      results[kDartDefines] = (argResults[useLegacyNames ? kDartDefines : FlutterOptions.kDartDefinesOption] as List<String>).join(',');
    }
+    results[kDeferredComponents] = 'false';
+    if (FlutterProject.current().manifest.deferredComponents != null && isDeferredComponentsTargets() && !isDebug()) {
+      results[kDeferredComponents] = 'true';
+    }
    if (argResults.wasParsed(useLegacyNames ? kExtraFrontEndOptions : FlutterOptions.kExtraFrontEndOptions)) {
      results[kExtraFrontEndOptions] = (argResults[useLegacyNames ? kExtraFrontEndOptions : FlutterOptions.kExtraFrontEndOptions] as List<String>).join(',');
    }
@@ -229,11 +259,37 @@ class AssembleCommand extends FlutterCommand {

  @override
  Future<FlutterCommandResult> runCommand() async {
+    final Environment env = createEnvironment();
    final List<Target> targets = createTargets();
-    final Target target = targets.length == 1 ? targets.single : CompositeTarget(targets);
+    final List<Target> nonDeferredTargets = <Target>[];
+    final List<Target> deferredTargets = <AndroidAotDeferredComponentsBundle>[];
+    for (final Target target in targets) {
+      if (deferredComponentsTargets.contains(target.name)) {
+        deferredTargets.add(target);
+      } else {
+        nonDeferredTargets.add(target);
+      }
+    }
+    Target target;
+    final List<String> decodedDefines = decodeDartDefines(env.defines, kDartDefines);
+    if (FlutterProject.current().manifest.deferredComponents != null
+        && decodedDefines.contains('validate-deferred-components=true')
+        && deferredTargets.isNotEmpty
+        && !isDebug()) {
+      // Add deferred components validation target that require loading units.
+      target = DeferredComponentsGenSnapshotValidatorTarget(
+        deferredComponentsDependencies: deferredTargets.cast<AndroidAotDeferredComponentsBundle>(),
+        nonDeferredComponentsDependencies: nonDeferredTargets,
+        title: 'Deferred components gen_snapshot validation',
+      );
+    } else if (targets.length > 1) {
+      target = CompositeTarget(targets);
+    } else if (targets.isNotEmpty) {
+      target = targets.single;
+    }
    final BuildResult result = await _buildSystem.build(
      target,
-      createEnvironment(),
+      env,
      buildSystemConfig: BuildSystemConfig(
        resourcePoolSize: argResults.wasParsed('resource-pool-size')
          ? int.tryParse(stringArg('resource-pool-size'))
@@ -251,6 +307,7 @@ class AssembleCommand extends FlutterCommand {
      throwToolExit('');
    }
    globals.printTrace('build succeeded.');
+
    if (argResults.wasParsed('build-inputs')) {
      writeListIfChanged(result.inputFiles, stringArg('build-inputs'));
    }

--- a/packages/flutter_tools/lib/src/commands/build_appbundle.dart
+++ b/packages/flutter_tools/lib/src/commands/build_appbundle.dart
@@ -6,7 +6,10 @@

 import '../android/android_builder.dart';
 import '../android/build_validation.dart';
+import '../android/deferred_components_prebuild_validator.dart';
 import '../android/gradle_utils.dart';
+import '../base/deferred_component.dart';
+import '../base/file_system.dart';
 import '../build_info.dart';
 import '../cache.dart';
 import '../globals.dart' as globals;
@@ -42,6 +45,25 @@ class BuildAppBundleCommand extends BuildSubCommand {
      allowed: <String>['android-arm', 'android-arm64', 'android-x64'],
      help: 'The target platform for which the app is compiled.',
    );
+    argParser.addFlag('deferred-components',
+      negatable: true,
+      defaultsTo: true,
+      help: 'Setting to false disables building with deferred components. All deferred code '
+            'will be compiled into the base app, and assets act as if they were defined under'
+            ' the regular assets section in pubspec.yaml. This flag has no effect on '
+            'non-deferred components apps.',
+    );
+    argParser.addFlag('validate-deferred-components',
+      negatable: true,
+      defaultsTo: true,
+      help: 'When enabled, deferred component apps will fail to build if setup problems are '
+            'detected that would prevent deferred components from functioning properly. The '
+            'tooling also provides guidance on how to set up the project files to pass this '
+            'verification. Disabling setup verification will always attempt to fully build '
+            'the app regardless of any problems detected. Builds that are part of CI testing '
+            'and advanced users with custom deferred components implementations should disable '
+            'setup verification. This flag has no effect on non-deferred components apps.',
+    );
  }

  @override
@@ -84,15 +106,49 @@ class BuildAppBundleCommand extends BuildSubCommand {
    if (globals.androidSdk == null) {
      exitWithNoSdkMessage();
    }
+
    final AndroidBuildInfo androidBuildInfo = AndroidBuildInfo(await getBuildInfo(),
      targetArchs: stringsArg('target-platform').map<AndroidArch>(getAndroidArchForName),
    );
+    // Do all setup verification that doesn't involve loading units. Checks that
+    // require generated loading units are done after gen_snapshot in assemble.
+    if (FlutterProject.current().manifest.deferredComponents != null && boolArg('deferred-components') && boolArg('validate-deferred-components') && !boolArg('debug')) {
+      final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
+        FlutterProject.current().directory,
+        globals.logger,
+        title: 'Deferred components prebuild validation',
+        exitOnFail: true,
+      );
+      validator.clearOutputDir();
+      await validator.checkAndroidDynamicFeature(FlutterProject.current().manifest.deferredComponents);
+      validator.checkAndroidResourcesStrings(FlutterProject.current().manifest.deferredComponents);
+
+      validator.handleResults();
+
+      // Delete intermediates libs dir for components to resolve mismatching
+      // abis supported by base and dynamic feature modules.
+      for (final DeferredComponent component in FlutterProject.current().manifest.deferredComponents) {
+        final Directory deferredLibsIntermediate = FlutterProject.current().directory
+          .childDirectory('build')
+          .childDirectory(component.name)
+          .childDirectory('intermediates')
+          .childDirectory('flutter')
+          .childDirectory(androidBuildInfo.buildInfo.mode.name)
+          .childDirectory('deferred_libs');
+        if (deferredLibsIntermediate.existsSync()) {
+          deferredLibsIntermediate.deleteSync(recursive: true);
+        }
+      }
+    }
+
    validateBuild(androidBuildInfo);
    displayNullSafetyMode(androidBuildInfo.buildInfo);
    await androidBuilder.buildAab(
      project: FlutterProject.current(),
      target: targetFile,
      androidBuildInfo: androidBuildInfo,
+      validateDeferredComponents: boolArg('validate-deferred-components'),
+      deferredComponentsEnabled: boolArg('deferred-components') && !boolArg('debug'),
    );
    return FlutterCommandResult.success();
  }

--- a/packages/flutter_tools/lib/src/runner/flutter_command.dart
+++ b/packages/flutter_tools/lib/src/runner/flutter_command.dart
@@ -120,6 +120,7 @@ class FlutterOptions {
  static const String kAnalyzeSize = 'analyze-size';
  static const String kNullAssertions = 'null-assertions';
  static const String kAndroidGradleDaemon = 'android-gradle-daemon';
+  static const String kDeferredComponents = 'deferred-components';
 }

 abstract class FlutterCommand extends Command<void> {

--- a/packages/flutter_tools/templates/module/android/deferred_component/build.gradle.tmpl
+++ b/packages/flutter_tools/templates/module/android/deferred_component/build.gradle.tmpl
+def localProperties = new Properties()
+def localPropertiesFile = rootProject.file('local.properties')
+if (localPropertiesFile.exists()) {
+    localPropertiesFile.withReader('UTF-8') { reader ->
+        localProperties.load(reader)
+    }
+}
+
+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.dynamic-feature"
+
+android {
+    compileSdkVersion 30
+
+    sourceSets {
+        applicationVariants.all { variant ->
+            main.assets.srcDirs += "${project.buildDir}/intermediates/flutter/${variant.name}/deferred_assets"
+            main.jniLibs.srcDirs += "${project.buildDir}/intermediates/flutter/${variant.name}/deferred_libs"
+        }
+    }
+
+    defaultConfig {
+        minSdkVersion 16
+        targetSdkVersion 30
+        versionCode flutterVersionCode.toInteger()
+        versionName flutterVersionName
+    }
+
+    compileOptions {
+        sourceCompatibility 1.8
+        targetCompatibility 1.8
+    }
+}
+
+dependencies {
+    implementation project(":app")
+}
--- a/packages/flutter_tools/templates/module/android/deferred_component/src/main/AndroidManifest.xml.tmpl
+++ b/packages/flutter_tools/templates/module/android/deferred_component/src/main/AndroidManifest.xml.tmpl
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:dist="http://schemas.android.com/apk/distribution"
+    package="{{androidIdentifier}}.{{componentName}}">
+
+    <dist:module
+        dist:instant="false"
+        dist:title="@string/{{componentName}}Name">
+        <dist:delivery>
+            <dist:on-demand />
+        </dist:delivery>
+        <dist:fusing dist:include="true" />
+    </dist:module>
+</manifest>
--- a/packages/flutter_tools/templates/template_manifest.json
+++ b/packages/flutter_tools/templates/template_manifest.json
@@ -140,6 +140,8 @@
        "templates/cocoapods/Podfile-ios-objc",
        "templates/cocoapods/Podfile-ios-swift",
        "templates/cocoapods/Podfile-macos",
+        "templates/module/android/deferred_component/build.gradle.tmpl",
+        "templates/module/android/deferred_component/src/main/AndroidManifest.xml.tmpl",
        "templates/module/android/gradle/build.gradle.copy.tmpl",
        "templates/module/android/gradle/gradle.properties.tmpl",
        "templates/module/android/host_app_common/app.tmpl/build.gradle.tmpl",

--- 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
@@ -22,7 +22,7 @@ void main() {
  Environment env;

  Environment createEnvironment() {
-    final Map<String, String> defines = <String, String>{ kSplitAot: 'true' };
+    final Map<String, String> defines = <String, String>{ kDeferredComponents: 'true' };
    final Environment result = Environment(
      outputDir: fileSystem.directory('/output'),
      buildDir: fileSystem.directory('/build'),

--- 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
@@ -10,9 +10,6 @@ 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/build_system/build_system.dart';
-import 'package:flutter_tools/src/build_system/targets/common.dart';
-import 'package:flutter_tools/src/globals.dart' as globals;

 import '../../src/common.dart';
 import '../../src/context.dart';
@@ -20,37 +17,20 @@ import '../../src/context.dart';
 void main() {
  FileSystem fileSystem;
  BufferLogger logger;
-  Environment env;
-
-  Environment createEnvironment() {
-    final Map<String, String> defines = <String, String>{ kSplitAot: 'true' };
-    final Environment result = Environment(
-      outputDir: fileSystem.directory('/output'),
-      buildDir: fileSystem.directory('/build'),
-      projectDir: fileSystem.directory('/project'),
-      defines: defines,
-      inputs: <String, String>{},
-      cacheDir: fileSystem.directory('/cache'),
-      flutterRootDir: fileSystem.directory('/flutter_root'),
-      artifacts: globals.artifacts,
-      fileSystem: fileSystem,
-      logger: logger,
-      processManager: globals.processManager,
-      engineVersion: 'invalidEngineVersion',
-      generateDartPluginRegistry: false,
-    );
-    return result;
-  }
+  Directory projectDir;
+  Directory flutterRootDir;

  setUp(() {
    fileSystem = MemoryFileSystem.test();
    logger = BufferLogger.test();
-    env = createEnvironment();
+    projectDir = fileSystem.directory('/project');
+    flutterRootDir = fileSystem.directory('/flutter_root');
  });

  testWithoutContext('No checks passes', () async {
    final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
-      env,
+      projectDir,
+      logger,
      exitOnFail: false,
      title: 'test check',
    );
@@ -61,7 +41,8 @@ void main() {

  testWithoutContext('clearTempDir passes', () async {
    final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
-      env,
+      projectDir,
+      logger,
      exitOnFail: false,
      title: 'test check',
    );
@@ -72,7 +53,7 @@ void main() {
  });

  testUsingContext('androidComponentSetup build.gradle does not exist', () async {
-    final Directory templatesDir = env.flutterRootDir.childDirectory('templates').childDirectory('deferred_component');
+    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');
    if (templatesDir.existsSync()) {
@@ -84,12 +65,13 @@ void main() {
    androidManifestTemplate.writeAsStringSync('fake AndroidManigest.xml template {{componentName}}', flush: true, mode: FileMode.append);

    final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
-      env,
+      projectDir,
+      logger,
      exitOnFail: false,
      title: 'test check',
      templatesDir: templatesDir,
    );
-    final Directory componentDir = env.projectDir.childDirectory('android').childDirectory('component1');
+    final Directory componentDir = projectDir.childDirectory('android').childDirectory('component1');
    final File file = componentDir.childDirectory('src').childDirectory('main').childFile('AndroidManifest.xml');
    if (file.existsSync()) {
      file.deleteSync();
@@ -109,7 +91,7 @@ void main() {
  });

  testUsingContext('androidComponentSetup AndroidManifest.xml does not exist', () async {
-    final Directory templatesDir = env.flutterRootDir.childDirectory('templates').childDirectory('deferred_component');
+    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');
    if (templatesDir.existsSync()) {
@@ -121,12 +103,13 @@ void main() {
    androidManifestTemplate.writeAsStringSync('fake AndroidManigest.xml template {{componentName}}', flush: true, mode: FileMode.append);

    final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
-      env,
+      projectDir,
+      logger,
      exitOnFail: false,
      title: 'test check',
      templatesDir: templatesDir,
    );
-    final Directory componentDir = env.projectDir.childDirectory('android').childDirectory('component1');
+    final Directory componentDir = projectDir.childDirectory('android').childDirectory('component1');
    final File file = componentDir.childFile('build.gradle');
    if (file.existsSync()) {
      file.deleteSync();
@@ -146,7 +129,7 @@ void main() {
  });

  testUsingContext('androidComponentSetup all files exist passes', () async {
-    final Directory templatesDir = env.flutterRootDir.childDirectory('templates').childDirectory('deferred_component');
+    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');
    if (templatesDir.existsSync()) {
@@ -158,12 +141,13 @@ void main() {
    androidManifestTemplate.writeAsStringSync('fake AndroidManigest.xml template {{componentName}}', flush: true, mode: FileMode.append);

    final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
-      env,
+      projectDir,
+      logger,
      exitOnFail: false,
      title: 'test check',
      templatesDir: templatesDir,
    );
-    final Directory componentDir = env.projectDir.childDirectory('android').childDirectory('component1');
+    final Directory componentDir = projectDir.childDirectory('android').childDirectory('component1');
    final File buildGradle = componentDir.childFile('build.gradle');
    if (buildGradle.existsSync()) {
      buildGradle.deleteSync();
@@ -189,11 +173,12 @@ void main() {

  testWithoutContext('androidStringMapping creates new file', () async {
    final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
-      env,
+      projectDir,
+      logger,
      exitOnFail: false,
      title: 'test check',
    );
-    final Directory baseModuleDir = env.projectDir.childDirectory('android').childDirectory('app');
+    final Directory baseModuleDir = projectDir.childDirectory('android').childDirectory('app');
    final File stringRes = baseModuleDir.childDirectory('src').childDirectory('main').childDirectory('res').childDirectory('values').childFile('strings.xml');
    if (stringRes.existsSync()) {
      stringRes.deleteSync();
@@ -239,7 +224,7 @@ void main() {
    expect(logger.statusText.contains('Newly generated android files:\n'), true);
    expect(logger.statusText.contains('build/${DeferredComponentsValidator.kDeferredComponentsTempDirectory}/app/src/main/res/values/strings.xml\n'), true);

-    final File stringsOutput = env.projectDir
+    final File stringsOutput = projectDir
      .childDirectory('build')
      .childDirectory(DeferredComponentsValidator.kDeferredComponentsTempDirectory)
      .childDirectory('app')
@@ -255,11 +240,12 @@ void main() {

  testWithoutContext('androidStringMapping modifies strings file', () async {
    final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
-      env,
+      projectDir,
+      logger,
      exitOnFail: false,
      title: 'test check',
    );
-    final Directory baseModuleDir = env.projectDir.childDirectory('android').childDirectory('app');
+    final Directory baseModuleDir = projectDir.childDirectory('android').childDirectory('app');
    final File stringRes = baseModuleDir.childDirectory('src').childDirectory('main').childDirectory('res').childDirectory('values').childFile('strings.xml');
    if (stringRes.existsSync()) {
      stringRes.deleteSync();
@@ -285,7 +271,7 @@ void main() {
    expect(logger.statusText.contains('Modified android files:\n'), true);
    expect(logger.statusText.contains('build/${DeferredComponentsValidator.kDeferredComponentsTempDirectory}/app/src/main/res/values/strings.xml\n'), true);

-    final File stringsOutput = env.projectDir
+    final File stringsOutput = projectDir
      .childDirectory('build')
      .childDirectory(DeferredComponentsValidator.kDeferredComponentsTempDirectory)
      .childDirectory('app')

--- a/packages/flutter_tools/test/general.shard/asset_bundle_test.dart
+++ b/packages/flutter_tools/test/general.shard/asset_bundle_test.dart
@@ -176,6 +176,129 @@ flutter:
      FileSystem: () => testFileSystem,
      ProcessManager: () => FakeProcessManager.any(),
    });
+
+    testUsingContext('deferred assets are parsed', () async {
+      globals.fs.file('.packages').createSync();
+      globals.fs.file(globals.fs.path.join('assets', 'foo', 'bar.txt')).createSync(recursive: true);
+      globals.fs.file(globals.fs.path.join('assets', 'bar', 'barbie.txt')).createSync(recursive: true);
+      globals.fs.file(globals.fs.path.join('assets', 'wild', 'dash.txt')).createSync(recursive: true);
+      globals.fs.file('pubspec.yaml')
+        ..createSync()
+        ..writeAsStringSync(r'''
+name: example
+flutter:
+  assets:
+    - assets/foo/
+  deferred-components:
+    - name: component1
+      assets:
+        - assets/bar/barbie.txt
+        - assets/wild/
+''');
+      final AssetBundle bundle = AssetBundleFactory.defaultInstance(
+        logger: globals.logger,
+        fileSystem: globals.fs,
+        platform: globals.platform,
+        splitDeferredAssets: true,
+      ).createBundle();
+      await bundle.build(manifestPath: 'pubspec.yaml', packagesPath: '.packages', deferredComponentsEnabled: true);
+      // Expected assets:
+      //  - asset manifest
+      //  - font manifest
+      //  - license file
+      //  - assets/foo/bar.txt
+      expect(bundle.entries.length, 4);
+      expect(bundle.deferredComponentsEntries.length, 1);
+      expect(bundle.deferredComponentsEntries['component1'].length, 2);
+      expect(bundle.needsBuild(manifestPath: 'pubspec.yaml'), false);
+    }, overrides: <Type, Generator>{
+      FileSystem: () => testFileSystem,
+      ProcessManager: () => FakeProcessManager.any(),
+    });
+
+    testUsingContext('deferred assets are parsed regularly when splitDeferredAssets Disabled', () async {
+      globals.fs.file('.packages').createSync();
+      globals.fs.file(globals.fs.path.join('assets', 'foo', 'bar.txt')).createSync(recursive: true);
+      globals.fs.file(globals.fs.path.join('assets', 'bar', 'barbie.txt')).createSync(recursive: true);
+      globals.fs.file(globals.fs.path.join('assets', 'wild', 'dash.txt')).createSync(recursive: true);
+      globals.fs.file('pubspec.yaml')
+        ..createSync()
+        ..writeAsStringSync(r'''
+name: example
+flutter:
+  assets:
+    - assets/foo/
+  deferred-components:
+    - name: component1
+      assets:
+        - assets/bar/barbie.txt
+        - assets/wild/
+''');
+      final AssetBundle bundle = AssetBundleFactory.instance.createBundle();
+      await bundle.build(manifestPath: 'pubspec.yaml', packagesPath: '.packages', deferredComponentsEnabled: false);
+      // Expected assets:
+      //  - asset manifest
+      //  - font manifest
+      //  - license file
+      //  - assets/foo/bar.txt
+      expect(bundle.entries.length, 6);
+      expect(bundle.deferredComponentsEntries.isEmpty, true);
+      expect(bundle.needsBuild(manifestPath: 'pubspec.yaml'), false);
+    }, overrides: <Type, Generator>{
+      FileSystem: () => testFileSystem,
+      ProcessManager: () => FakeProcessManager.any(),
+    });
+
+    testUsingContext('deferred assets wildcard parsed', () async {
+      final File packageFile = globals.fs.file('.packages')..createSync();
+      globals.fs.file(globals.fs.path.join('assets', 'foo', 'bar.txt')).createSync(recursive: true);
+      globals.fs.file(globals.fs.path.join('assets', 'bar', 'barbie.txt')).createSync(recursive: true);
+      globals.fs.file(globals.fs.path.join('assets', 'wild', 'dash.txt')).createSync(recursive: true);
+      globals.fs.file('pubspec.yaml')
+        ..createSync()
+        ..writeAsStringSync(r'''
+name: example
+flutter:
+  assets:
+    - assets/foo/
+  deferred-components:
+    - name: component1
+      assets:
+        - assets/bar/barbie.txt
+        - assets/wild/
+''');
+      final AssetBundle bundle = AssetBundleFactory.defaultInstance(
+        logger: globals.logger,
+        fileSystem: globals.fs,
+        platform: globals.platform,
+        splitDeferredAssets: true,
+      ).createBundle();
+      await bundle.build(manifestPath: 'pubspec.yaml', packagesPath: '.packages', deferredComponentsEnabled: true);
+      // Expected assets:
+      //  - asset manifest
+      //  - font manifest
+      //  - license file
+      //  - assets/foo/bar.txt
+      expect(bundle.entries.length, 4);
+      expect(bundle.deferredComponentsEntries.length, 1);
+      expect(bundle.deferredComponentsEntries['component1'].length, 2);
+      expect(bundle.needsBuild(manifestPath: 'pubspec.yaml'), false);
+
+      // Simulate modifying the files by updating the filestat time manually.
+      globals.fs.file(globals.fs.path.join('assets', 'wild', 'fizz.txt'))
+        ..createSync(recursive: true)
+        ..setLastModifiedSync(packageFile.lastModifiedSync().add(const Duration(hours: 1)));
+
+      expect(bundle.needsBuild(manifestPath: 'pubspec.yaml'), true);
+      await bundle.build(manifestPath: 'pubspec.yaml', packagesPath: '.packages', deferredComponentsEnabled: true);
+
+      expect(bundle.entries.length, 4);
+      expect(bundle.deferredComponentsEntries.length, 1);
+      expect(bundle.deferredComponentsEntries['component1'].length, 3);
+    }, overrides: <Type, Generator>{
+      FileSystem: () => testFileSystem,
+      ProcessManager: () => FakeProcessManager.any(),
+    });
  });

  testUsingContext('Failed directory delete shows message', () async {

--- a/packages/flutter_tools/test/general.shard/base/command_help_test.dart
+++ b/packages/flutter_tools/test/general.shard/base/command_help_test.dart
@@ -130,16 +130,16 @@ void main() {
          wrapColumn: maxLineWidth,
        );

-        expect(commandHelp.L.toString(), endsWith('\x1B[1;30m(debugDumpLayerTree)\x1B[39m\x1b[22m'));
-        expect(commandHelp.P.toString(), endsWith('\x1B[1;30m(WidgetsApp.showPerformanceOverlay)\x1B[39m\x1b[22m'));
-        expect(commandHelp.S.toString(), endsWith('\x1B[1;30m(debugDumpSemantics)\x1B[39m\x1b[22m'));
-        expect(commandHelp.U.toString(), endsWith('\x1B[1;30m(debugDumpSemantics)\x1B[39m\x1b[22m'));
-        expect(commandHelp.a.toString(), endsWith('\x1B[1;30m(debugProfileWidgetBuilds)\x1B[39m\x1b[22m'));
-        expect(commandHelp.i.toString(), endsWith('\x1B[1;30m(WidgetsApp.showWidgetInspectorOverride)\x1B[39m\x1b[22m'));
-        expect(commandHelp.o.toString(), endsWith('\x1B[1;30m(defaultTargetPlatform)\x1B[39m\x1b[22m'));
-        expect(commandHelp.p.toString(), endsWith('\x1B[1;30m(debugPaintSizeEnabled)\x1B[39m\x1b[22m'));
-        expect(commandHelp.t.toString(), endsWith('\x1B[1;30m(debugDumpRenderTree)\x1B[39m\x1b[22m'));
-        expect(commandHelp.w.toString(), endsWith('\x1B[1;30m(debugDumpApp)\x1B[39m\x1b[22m'));
+        expect(commandHelp.L.toString(), endsWith('\x1B[90m(debugDumpLayerTree)\x1B[39m\x1b[22m'));
+        expect(commandHelp.P.toString(), endsWith('\x1B[90m(WidgetsApp.showPerformanceOverlay)\x1B[39m\x1b[22m'));
+        expect(commandHelp.S.toString(), endsWith('\x1B[90m(debugDumpSemantics)\x1B[39m\x1b[22m'));
+        expect(commandHelp.U.toString(), endsWith('\x1B[90m(debugDumpSemantics)\x1B[39m\x1b[22m'));
+        expect(commandHelp.a.toString(), endsWith('\x1B[90m(debugProfileWidgetBuilds)\x1B[39m\x1b[22m'));
+        expect(commandHelp.i.toString(), endsWith('\x1B[90m(WidgetsApp.showWidgetInspectorOverride)\x1B[39m\x1b[22m'));
+        expect(commandHelp.o.toString(), endsWith('\x1B[90m(defaultTargetPlatform)\x1B[39m\x1b[22m'));
+        expect(commandHelp.p.toString(), endsWith('\x1B[90m(debugPaintSizeEnabled)\x1B[39m\x1b[22m'));
+        expect(commandHelp.t.toString(), endsWith('\x1B[90m(debugDumpRenderTree)\x1B[39m\x1b[22m'));
+        expect(commandHelp.w.toString(), endsWith('\x1B[90m(debugDumpApp)\x1B[39m\x1b[22m'));
      });

      testWithoutContext('should not create a help text longer than maxLineWidth without ansi support', () {
@@ -180,24 +180,24 @@ void main() {
          wrapColumn: maxLineWidth,
        );

-        expect(commandHelp.L.toString(), equals('\x1B[1mL\x1B[22m Dump layer tree to the console.                               \x1B[1;30m(debugDumpLayerTree)\x1B[39m\x1b[22m'));
-        expect(commandHelp.P.toString(), equals('\x1B[1mP\x1B[22m Toggle performance overlay.                    \x1B[1;30m(WidgetsApp.showPerformanceOverlay)\x1B[39m\x1b[22m'));
+        expect(commandHelp.L.toString(), equals('\x1B[1mL\x1B[22m Dump layer tree to the console.                               \x1B[90m(debugDumpLayerTree)\x1B[39m\x1b[22m'));
+        expect(commandHelp.P.toString(), equals('\x1B[1mP\x1B[22m Toggle performance overlay.                    \x1B[90m(WidgetsApp.showPerformanceOverlay)\x1B[39m\x1b[22m'));
        expect(commandHelp.R.toString(), equals('\x1B[1mR\x1B[22m Hot restart.'));
-        expect(commandHelp.S.toString(), equals('\x1B[1mS\x1B[22m Dump accessibility tree in traversal order.                   \x1B[1;30m(debugDumpSemantics)\x1B[39m\x1b[22m'));
-        expect(commandHelp.U.toString(), equals('\x1B[1mU\x1B[22m Dump accessibility tree in inverse hit test order.            \x1B[1;30m(debugDumpSemantics)\x1B[39m\x1b[22m'));
-        expect(commandHelp.a.toString(), equals('\x1B[1ma\x1B[22m Toggle timeline events for all widget build methods.    \x1B[1;30m(debugProfileWidgetBuilds)\x1B[39m\x1b[22m'));
+        expect(commandHelp.S.toString(), equals('\x1B[1mS\x1B[22m Dump accessibility tree in traversal order.                   \x1B[90m(debugDumpSemantics)\x1B[39m\x1b[22m'));
+        expect(commandHelp.U.toString(), equals('\x1B[1mU\x1B[22m Dump accessibility tree in inverse hit test order.            \x1B[90m(debugDumpSemantics)\x1B[39m\x1b[22m'));
+        expect(commandHelp.a.toString(), equals('\x1B[1ma\x1B[22m Toggle timeline events for all widget build methods.    \x1B[90m(debugProfileWidgetBuilds)\x1B[39m\x1b[22m'));
        expect(commandHelp.d.toString(), equals('\x1B[1md\x1B[22m Detach (terminate "flutter run" but leave application running).'));
        expect(commandHelp.g.toString(), equals('\x1B[1mg\x1B[22m Run source code generators.'));
        expect(commandHelp.h.toString(), equals('\x1B[1mh\x1B[22m Repeat this help message.'));
-        expect(commandHelp.i.toString(), equals('\x1B[1mi\x1B[22m Toggle widget inspector.                  \x1B[1;30m(WidgetsApp.showWidgetInspectorOverride)\x1B[39m\x1b[22m'));
-        expect(commandHelp.o.toString(), equals('\x1B[1mo\x1B[22m Simulate different operating systems.                      \x1B[1;30m(defaultTargetPlatform)\x1B[39m\x1b[22m'));
-        expect(commandHelp.p.toString(), equals('\x1B[1mp\x1B[22m Toggle the display of construction lines.                  \x1B[1;30m(debugPaintSizeEnabled)\x1B[39m\x1b[22m'));
+        expect(commandHelp.i.toString(), equals('\x1B[1mi\x1B[22m Toggle widget inspector.                  \x1B[90m(WidgetsApp.showWidgetInspectorOverride)\x1B[39m\x1b[22m'));
+        expect(commandHelp.o.toString(), equals('\x1B[1mo\x1B[22m Simulate different operating systems.                      \x1B[90m(defaultTargetPlatform)\x1B[39m\x1b[22m'));
+        expect(commandHelp.p.toString(), equals('\x1B[1mp\x1B[22m Toggle the display of construction lines.                  \x1B[90m(debugPaintSizeEnabled)\x1B[39m\x1b[22m'));
        expect(commandHelp.q.toString(), equals('\x1B[1mq\x1B[22m Quit (terminate the application on the device).'));
        expect(commandHelp.r.toString(), equals('\x1B[1mr\x1B[22m Hot reload. $fire$fire$fire'));
        expect(commandHelp.s.toString(), equals('\x1B[1ms\x1B[22m Save a screenshot to flutter.png.'));
-        expect(commandHelp.t.toString(), equals('\x1B[1mt\x1B[22m Dump rendering tree to the console.                          \x1B[1;30m(debugDumpRenderTree)\x1B[39m\x1b[22m'));
+        expect(commandHelp.t.toString(), equals('\x1B[1mt\x1B[22m Dump rendering tree to the console.                          \x1B[90m(debugDumpRenderTree)\x1B[39m\x1b[22m'));
        expect(commandHelp.v.toString(), equals('\x1B[1mv\x1B[22m Launch DevTools.'));
-        expect(commandHelp.w.toString(), equals('\x1B[1mw\x1B[22m Dump widget hierarchy to the console.                               \x1B[1;30m(debugDumpApp)\x1B[39m\x1b[22m'));
+        expect(commandHelp.w.toString(), equals('\x1B[1mw\x1B[22m Dump widget hierarchy to the console.                               \x1B[90m(debugDumpApp)\x1B[39m\x1b[22m'));
        expect(commandHelp.z.toString(), equals('\x1B[1mz\x1B[22m Toggle elevation checker.'));
      });


--- a/packages/flutter_tools/test/general.shard/build_system/targets/deferred_components_test.dart
+++ b/packages/flutter_tools/test/general.shard/build_system/targets/deferred_components_test.dart
@@ -34,7 +34,7 @@ void main() {
      buildDir: fileSystem.directory('build')..createSync(),
      projectDir: fileSystem.directory('project')..createSync(),
      defines: <String, String>{
-        kSplitAot: 'true',
+        kDeferredComponents: 'true',
      },
      artifacts: null,
      processManager: null,
@@ -44,11 +44,10 @@ void main() {
    environment.buildDir.createSync(recursive: true);
    const AndroidAot androidAot = AndroidAot(TargetPlatform.android_arm64, BuildMode.release);
    const AndroidAotBundle androidAotBundle = AndroidAotBundle(androidAot);
-    final CompositeTarget androidDefBundle = CompositeTarget(<Target>[androidAotBundle]);
-    final CompositeTarget compositeTarget = CompositeTarget(<Target>[androidDefBundle]);
+    final AndroidAotDeferredComponentsBundle androidDefBundle = AndroidAotDeferredComponentsBundle(androidAotBundle);
    final DeferredComponentsGenSnapshotValidatorTarget validatorTarget = DeferredComponentsGenSnapshotValidatorTarget(
-      dependency: compositeTarget,
-      abis: <String>['arm64-v8a'],
+      deferredComponentsDependencies: <AndroidAotDeferredComponentsBundle>[androidDefBundle],
+      nonDeferredComponentsDependencies: <Target>[],
      title: 'test checks',
      exitOnFail: false,
    );
@@ -68,7 +67,7 @@ void main() {
      buildDir: fileSystem.directory('build')..createSync(),
      projectDir: fileSystem.directory('project')..createSync(),
      defines: <String, String>{
-        kSplitAot: 'true',
+        kDeferredComponents: 'true',
      },
      artifacts: null,
      processManager: null,
@@ -78,11 +77,10 @@ void main() {
    environment.buildDir.createSync(recursive: true);
    const AndroidAot androidAot = AndroidAot(TargetPlatform.android_arm64, BuildMode.release);
    const AndroidAotBundle androidAotBundle = AndroidAotBundle(androidAot);
-    final CompositeTarget androidDefBundle = CompositeTarget(<Target>[androidAotBundle]);
-    final CompositeTarget compositeTarget = CompositeTarget(<Target>[androidDefBundle]);
+    final AndroidAotDeferredComponentsBundle androidDefBundle = AndroidAotDeferredComponentsBundle(androidAotBundle);
    final DeferredComponentsGenSnapshotValidatorTarget validatorTarget = DeferredComponentsGenSnapshotValidatorTarget(
-      dependency: compositeTarget,
-      abis: <String>['arm64-v8a'],
+      deferredComponentsDependencies: <AndroidAotDeferredComponentsBundle>[androidDefBundle],
+      nonDeferredComponentsDependencies: <Target>[],
      title: 'test checks',
      exitOnFail: false,
    );
@@ -101,7 +99,7 @@ void main() {
      buildDir: fileSystem.directory('build')..createSync(),
      projectDir: fileSystem.directory('project')..createSync(),
      defines: <String, String>{
-        kSplitAot: 'true',
+        kDeferredComponents: 'true',
      },
      artifacts: null,
      processManager: null,
@@ -111,11 +109,10 @@ void main() {
    environment.buildDir.createSync(recursive: true);
    const AndroidAot androidAot = AndroidAot(TargetPlatform.android_arm64, BuildMode.release);
    const AndroidAotBundle androidAotBundle = AndroidAotBundle(androidAot);
-    final CompositeTarget androidDefBundle = CompositeTarget(<Target>[androidAotBundle]);
-    final CompositeTarget compositeTarget = CompositeTarget(<Target>[androidDefBundle]);
+    final AndroidAotDeferredComponentsBundle androidDefBundle = AndroidAotDeferredComponentsBundle(androidAotBundle);
    final DeferredComponentsGenSnapshotValidatorTarget validatorTarget = DeferredComponentsGenSnapshotValidatorTarget(
-      dependency: compositeTarget,
-      abis: <String>['arm64-v8a'],
+      deferredComponentsDependencies: <AndroidAotDeferredComponentsBundle>[androidDefBundle],
+      nonDeferredComponentsDependencies: <Target>[],
      title: 'test checks',
      exitOnFail: false,
    );

--- a/packages/flutter_tools/test/integration.shard/deferred_components_test.dart
+++ b/packages/flutter_tools/test/integration.shard/deferred_components_test.dart
--- a/packages/flutter_tools/test/integration.shard/test_data/deferred_components_config.dart
+++ b/packages/flutter_tools/test/integration.shard/test_data/deferred_components_config.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 = 2.8
+
+import 'package:file/file.dart';
+
+import '../test_utils.dart';
+
+abstract class DeferredComponentsConfig {
+  String get deferredLibrary;
+  String get deferredComponentsGolden;
+  String get androidSettings;
+  String get androidBuild;
+  String get androidLocalProperties;
+  String get androidGradleProperties;
+  String get androidKeyProperties;
+  List<int> get androidKey;
+  String get appBuild;
+  String get appManifest;
+  String get appStrings;
+  String get appStyles;
+  String get appLaunchBackground;
+  String get asset1;
+  String get asset2;
+  List<DeferredComponentModule> get deferredComponents;
+
+  void setUpIn(Directory dir) {
+    if (deferredLibrary != null) {
+      writeFile(fileSystem.path.join(dir.path, 'lib', 'deferred_library.dart'), deferredLibrary);
+    }
+    if (deferredComponentsGolden != null) {
+      writeFile(fileSystem.path.join(dir.path, 'deferred_components_loading_units.yaml'), deferredComponentsGolden);
+    }
+    if (androidSettings != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'settings.gradle'), androidSettings);
+    }
+    if (androidBuild != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'build.gradle'), androidBuild);
+    }
+    if (androidLocalProperties != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'local.properties'), androidLocalProperties);
+    }
+    if (androidGradleProperties != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'gradle.properties'), androidGradleProperties);
+    }
+    if (androidKeyProperties != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'key.properties'), androidKeyProperties);
+    }
+    if (androidKey != null) {
+      writeBytesFile(fileSystem.path.join(dir.path, 'android', 'app', 'key.jks'), androidKey);
+    }
+    if (appBuild != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'app', 'build.gradle'), appBuild);
+    }
+    if (appManifest != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'app', 'src', 'main', 'AndroidManifest.xml'), appManifest);
+    }
+    if (appStrings != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'app', 'src', 'main', 'res', 'values', 'strings.xml'), appStrings);
+    }
+    if (appStyles != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'app', 'src', 'main', 'res', 'values', 'styles.xml'), appStyles);
+    }
+    if (appLaunchBackground != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'app', 'src', 'main', 'res', 'drawable', 'launch_background.xml'), appLaunchBackground);
+    }
+    if (asset1 != null) {
+      writeFile(fileSystem.path.join(dir.path, 'test_assets/asset1.txt'), asset1);
+    }
+    if (asset2 != null) {
+      writeFile(fileSystem.path.join(dir.path, 'test_assets/asset2.txt'), asset2);
+    }
+    if (deferredComponents != null) {
+      for (final DeferredComponentModule component in deferredComponents) {
+        component.setUpIn(dir);
+      }
+    }
+  }
+}
+
+class DeferredComponentModule {
+  DeferredComponentModule(this.name);
+
+  String name;
+
+  void setUpIn(Directory dir) {
+    if (name != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', name, 'build.gradle'), r'''
+      def localProperties = new Properties()
+      def localPropertiesFile = rootProject.file('local.properties')
+      if (localPropertiesFile.exists()) {
+          localPropertiesFile.withReader('UTF-8') { reader ->
+              localProperties.load(reader)
+          }
+      }
+
+      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.dynamic-feature"
+
+      android {
+          compileSdkVersion 30
+
+          sourceSets {
+              applicationVariants.all { variant ->
+                  main.assets.srcDirs += "${project.buildDir}/intermediates/flutter/${variant.name}/deferred_assets"
+                  main.jniLibs.srcDirs += "${project.buildDir}/intermediates/flutter/${variant.name}/deferred_libs"
+              }
+          }
+
+          defaultConfig {
+              minSdkVersion 16
+              targetSdkVersion 30
+              versionCode flutterVersionCode.toInteger()
+              versionName flutterVersionName
+          }
+          compileOptions {
+              sourceCompatibility 1.8
+              targetCompatibility 1.8
+          }
+      }
+
+      dependencies {
+          implementation project(":app")
+      }
+      ''');
+
+      writeFile(fileSystem.path.join(dir.path, 'android', name, 'src', 'main', 'AndroidManifest.xml'), '''
+      <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          xmlns:dist="http://schemas.android.com/apk/distribution"
+          package="com.example.$name">
+
+          <dist:module
+              dist:instant="false"
+              dist:title="@string/component1Name">
+              <dist:delivery>
+                  <dist:on-demand />
+              </dist:delivery>
+              <dist:fusing dist:include="true" />
+          </dist:module>
+      </manifest>
+      ''');
+    }
+  }
+}
\ No newline at end of file
--- a/packages/flutter_tools/test/integration.shard/test_data/deferred_components_project.dart
+++ b/packages/flutter_tools/test/integration.shard/test_data/deferred_components_project.dart
--- a/packages/flutter_tools/test/integration.shard/test_data/project.dart
+++ b/packages/flutter_tools/test/integration.shard/test_data/project.dart
@@ -7,6 +7,7 @@
 import 'package:file/file.dart';

 import '../test_utils.dart';
+import 'deferred_components_config.dart';

 const String _kDefaultHtml  = '''
 <html>
@@ -26,6 +27,7 @@ abstract class Project {
  String get main;
  String get test => null;
  String get generatedFile => null;
+  DeferredComponentsConfig get deferredComponents => null;

  Uri get mainDart => Uri.parse('package:test/main.dart');

@@ -41,6 +43,9 @@ abstract class Project {
    if (generatedFile != null) {
      writeFile(fileSystem.path.join(dir.path, '.dart_tool', 'flutter_gen', 'flutter_gen.dart'), generatedFile);
    }
+    if (deferredComponents != null) {
+      deferredComponents.setUpIn(dir);
+    }
    writeFile(fileSystem.path.join(dir.path, 'web', 'index.html'), _kDefaultHtml);
    writePackages(dir.path);
    await getPackages(dir.path);

--- a/packages/flutter_tools/test/integration.shard/test_utils.dart
+++ b/packages/flutter_tools/test/integration.shard/test_utils.dart
@@ -40,6 +40,13 @@ void writeFile(String path, String content) {
    ..setLastModifiedSync(DateTime.now().add(const Duration(seconds: 10)));
 }

+void writeBytesFile(String path, List<int> content) {
+  fileSystem.file(path)
+    ..createSync(recursive: true)
+    ..writeAsBytesSync(content)
+    ..setLastModifiedSync(DateTime.now().add(const Duration(seconds: 10)));
+}
+
 void writePackages(String folder) {
  writeFile(fileSystem.path.join(folder, '.packages'), '''
 test:${fileSystem.path.join(fileSystem.currentDirectory.path, 'lib')}/

--- a/packages/flutter_tools/test/src/android_common.dart
+++ b/packages/flutter_tools/test/src/android_common.dart
@@ -35,6 +35,8 @@ class FakeAndroidBuilder implements AndroidBuilder {
    @required FlutterProject project,
    @required AndroidBuildInfo androidBuildInfo,
    @required String target,
+    bool validateDeferredComponents = true,
+    bool deferredComponentsEnabled = false,
  }) async {}
 }


--- a/packages/flutter_tools/test/src/common.dart
+++ b/packages/flutter_tools/test/src/common.dart
@@ -90,6 +90,15 @@ String getFlutterRoot() {
  return path.normalize(path.join(toolsPath, '..', '..'));
 }

+/// Gets the path to the root of the Android SDK from the environment variable.
+String getAndroidSdkRoot() {
+  const Platform platform = LocalPlatform();
+  if (platform.environment.containsKey('ANDROID_SDK_ROOT')) {
+    return platform.environment['ANDROID_SDK_ROOT'];
+  }
+  throw StateError('ANDROID_SDK_ROOT environment varible not set');
+}
+
 CommandRunner<void> createTestCommandRunner([ FlutterCommand command ]) {
  final FlutterCommandRunner runner = TestFlutterCommandRunner();
  if (command != null) {