Font subset in the tool (#49737)

dev/devicelab/lib/tasks/perf_tests.dart

@@ -422,6 +422,7 @@ class CompileTest {
       case DeviceOperatingSystem.android:
         options.insert(0, 'apk');
         options.add('--target-platform=android-arm');
+        options.add('--tree-shake-icons');
         watch.start();
         await flutter('build', options: options);
         watch.stop();

packages/flutter_tools/bin/macos_assemble.sh

@@ -62,6 +62,11 @@ ephemeral_dir="${SOURCE_ROOT}/Flutter/ephemeral"
 build_inputs_path="${ephemeral_dir}/FlutterInputs.xcfilelist"
 build_outputs_path="${ephemeral_dir}/FlutterOutputs.xcfilelist"
 
+icon_tree_shaker_flag="false"
+if [[ -n "$TREE_SHAKE_ICONS" ]]; then
+  icon_tree_shaker_flag="true"
+fi
+
 RunCommand "${FLUTTER_ROOT}/bin/flutter" --suppress-analytics               \
     ${verbose_flag}                                                         \
     ${flutter_engine_flag}                                                  \
@@ -70,6 +75,7 @@ RunCommand "${FLUTTER_ROOT}/bin/flutter" --suppress-analytics               \
     -dTargetPlatform=darwin-x64                                             \
     -dTargetFile="${target_path}"                                           \
     -dBuildMode="${build_mode}"                                             \
+    -dFontSubset="${icon_tree_shaker_flag}"                                      \
     --build-inputs="${build_inputs_path}"                                   \
     --build-outputs="${build_outputs_path}"                                 \
     --output="${ephemeral_dir}"                                             \

packages/flutter_tools/gradle/flutter.gradle

@@ -603,6 +603,10 @@ class FlutterPlugin implements Plugin<Project> {
         if (project.hasProperty('extra-gen-snapshot-options')) {
             extraGenSnapshotOptionsValue = project.property('extra-gen-snapshot-options')
         }
+        Boolean treeShakeIconsOptionsValue = false
+        if (project.hasProperty('tree-shake-icons')) {
+            treeShakeIconsOptionsValue = project.property('tree-shake-icons').toBoolean()
+        }
         def targetPlatforms = getTargetPlatforms()
         def addFlutterDeps = { variant ->
             if (shouldSplitPerAbi()) {
@@ -637,6 +641,7 @@ class FlutterPlugin implements Plugin<Project> {
                 intermediateDir project.file("${project.buildDir}/${AndroidProject.FD_INTERMEDIATES}/flutter/${variant.name}/")
                 extraFrontEndOptions extraFrontEndOptionsValue
                 extraGenSnapshotOptions extraGenSnapshotOptionsValue
+                treeShakeIcons treeShakeIconsOptionsValue
             }
             File libJar = project.file("${project.buildDir}/${AndroidProject.FD_INTERMEDIATES}/flutter/${variant.name}/libs.jar")
             Task packFlutterAppAotTask = project.tasks.create(name: "packLibs${FLUTTER_BUILD_PREFIX}${variant.name.capitalize()}", type: Jar) {
@@ -769,6 +774,8 @@ abstract class BaseFlutterTask extends DefaultTask {
     String extraFrontEndOptions
     @Optional @Input
     String extraGenSnapshotOptions
+    @Optional @Input
+    Boolean treeShakeIcons
 
     @OutputFiles
     FileCollection getDependenciesFiles() {
@@ -825,6 +832,9 @@ abstract class BaseFlutterTask extends DefaultTask {
             if (extraFrontEndOptions != null) {
                 args "-dExtraFrontEndOptions=${extraFrontEndOptions}"
             }
+            if (treeShakeIcons == true) {
+                args "-dTreeShakeIcons=true"
+            }
             if (extraGenSnapshotOptions != null) {
                 args "--ExtraGenSnapshotOptions=${extraGenSnapshotOptions}"
             }

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

@@ -338,6 +338,9 @@ Future<void> buildGradleApp({
   if (androidBuildInfo.fastStart) {
     command.add('-Pfast-start=true');
   }
+  if (androidBuildInfo.buildInfo.treeShakeIcons) {
+    command.add('-Ptree-shake-icons=true');
+  }
   command.add(assembleTask);
 
   GradleHandledError detectedGradleError;
@@ -546,6 +549,9 @@ Future<void> buildGradleAar({
     command.add('-Plocal-engine-repo=${localEngineRepo.path}');
     command.add('-Plocal-engine-build-mode=${androidBuildInfo.buildInfo.modeName}');
     command.add('-Plocal-engine-out=${localEngineArtifacts.engineOutPath}');
+    if (androidBuildInfo.buildInfo.treeShakeIcons) {
+      command.add('-Pfont-subset=true');
+    }
 
     // Copy the local engine repo in the output directory.
     try {
@@ -738,10 +744,11 @@ Future<void> buildPluginsAsAar(
     try {
       await buildGradleAar(
         project: FlutterProject.fromDirectory(pluginDirectory),
-        androidBuildInfo: const AndroidBuildInfo(
+        androidBuildInfo: AndroidBuildInfo(
           BuildInfo(
             BuildMode.release, // Plugins are built as release.
             null, // Plugins don't define flavors.
+            treeShakeIcons: androidBuildInfo.buildInfo.treeShakeIcons,
           ),
         ),
         target: '',

packages/flutter_tools/lib/src/aot.dart

@@ -36,6 +36,7 @@ class AotBuilder {
     List<String> extraFrontEndOptions,
     List<String> extraGenSnapshotOptions,
     @required List<String> dartDefines,
+    @required bool treeShakeIcons,
   }) async {
     if (platform == null) {
       throwToolExit('No AOT build platform specified');

packages/flutter_tools/lib/src/artifacts.dart

@@ -367,7 +367,10 @@ class CachedArtifacts extends Artifacts {
         return _fileSystem.path.join(dartPackageDirectory.path,  _artifactToFileName(artifact));
       case Artifact.fontSubset:
       case Artifact.constFinder:
-        return _cache.getArtifactDirectory('font-subset').childFile(_artifactToFileName(artifact, platform, mode)).path;
+        return _cache.getArtifactDirectory('engine')
+                     .childDirectory(getNameForTargetPlatform(platform))
+                     .childFile(_artifactToFileName(artifact, platform, mode))
+                     .path;
       default:
         assert(false, 'Artifact $artifact not available for platform $platform.');
         return null;

packages/flutter_tools/lib/src/asset.dart

@@ -21,6 +21,8 @@ const AssetBundleFactory _kManifestFactory = _ManifestAssetBundleFactory();
 
 const String defaultManifestPath = 'pubspec.yaml';
 
+const String kFontManifestJson = 'FontManifest.json';
+
 /// Injected factory class for spawning [AssetBundle] instances.
 abstract class AssetBundleFactory {
   /// The singleton instance, pulled from the [AppContext].
@@ -71,7 +73,6 @@ class _ManifestAssetBundle implements AssetBundle {
   DateTime _lastBuildTimestamp;
 
   static const String _assetManifestJson = 'AssetManifest.json';
-  static const String _fontManifestJson = 'FontManifest.json';
   static const String _fontSetMaterial = 'material';
   static const String _license = 'LICENSE';
 
@@ -242,7 +243,7 @@ class _ManifestAssetBundle implements AssetBundle {
 
     entries[_assetManifestJson] = _createAssetManifest(assetVariants);
 
-    entries[_fontManifestJson] = DevFSStringContent(json.encode(fonts));
+    entries[kFontManifestJson] = DevFSStringContent(json.encode(fonts));
 
     // TODO(ianh): Only do the following line if we've changed packages or if our LICENSE file changed
     entries[_license] = _obtainLicenses(packageMap, assetBasePath, reportPackages: reportLicensedPackages);

packages/flutter_tools/lib/src/build_info.dart

@@ -2,8 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:meta/meta.dart';
+
 import 'base/context.dart';
 import 'base/utils.dart';
+import 'build_system/targets/icon_tree_shaker.dart';
 import 'globals.dart' as globals;
 
 /// Information about a build to be performed or used.
@@ -18,10 +21,14 @@ class BuildInfo {
     this.fileSystemScheme,
     this.buildNumber,
     this.buildName,
+    @required this.treeShakeIcons,
   });
 
   final BuildMode mode;
 
+  /// Whether the build should subdset icon fonts.
+  final bool treeShakeIcons;
+
   /// Represents a custom Android product flavor or an Xcode scheme, null for
   /// using the default.
   ///
@@ -55,10 +62,10 @@ class BuildInfo {
   /// On Xcode builds it is used as CFBundleShortVersionString,
   final String buildName;
 
-  static const BuildInfo debug = BuildInfo(BuildMode.debug, null);
-  static const BuildInfo profile = BuildInfo(BuildMode.profile, null);
-  static const BuildInfo jitRelease = BuildInfo(BuildMode.jitRelease, null);
-  static const BuildInfo release = BuildInfo(BuildMode.release, null);
+  static const BuildInfo debug = BuildInfo(BuildMode.debug, null, treeShakeIcons: false);
+  static const BuildInfo profile = BuildInfo(BuildMode.profile, null, treeShakeIcons: kIconTreeShakerEnabledDefault);
+  static const BuildInfo jitRelease = BuildInfo(BuildMode.jitRelease, null, treeShakeIcons: kIconTreeShakerEnabledDefault);
+  static const BuildInfo release = BuildInfo(BuildMode.release, null, treeShakeIcons: kIconTreeShakerEnabledDefault);
 
   /// Returns whether a debug build is requested.
   ///

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

@@ -12,6 +12,7 @@ import '../depfile.dart';
 import '../exceptions.dart';
 import 'assets.dart';
 import 'dart.dart';
+import 'icon_tree_shaker.dart';
 
 /// Prepares the asset bundle in the format expected by flutter.gradle.
 ///
@@ -25,6 +26,7 @@ abstract class AndroidAssetBundle extends Target {
   @override
   List<Source> get inputs => const <Source>[
     Source.pattern('{BUILD_DIR}/app.dill'),
+    ...IconTreeShaker.inputs,
   ];
 
   @override

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

@@ -12,6 +12,8 @@ import '../../plugins.dart';
 import '../../project.dart';
 import '../build_system.dart';
 import '../depfile.dart';
+import 'dart.dart';
+import 'icon_tree_shaker.dart';
 
 /// A helper function to copy an asset bundle into an [environment]'s output
 /// directory.
@@ -31,6 +33,16 @@ Future<Depfile> copyAssets(Environment environment, Directory outputDirectory) a
     pubspecFile,
   ];
   final List<File> outputs = <File>[];
+
+  final IconTreeShaker iconTreeShaker = IconTreeShaker(
+    environment,
+    assetBundle.entries[kFontManifestJson] as DevFSStringContent,
+    processManager: globals.processManager,
+    logger: globals.logger,
+    fileSystem: globals.fs,
+    artifacts: globals.artifacts,
+  );
+
   await Future.wait<void>(
     assetBundle.entries.entries.map<Future<void>>((MapEntry<String, DevFSContent> entry) async {
       final PoolResource resource = await pool.request();
@@ -46,7 +58,13 @@ Future<Depfile> copyAssets(Environment environment, Directory outputDirectory) a
         final DevFSContent content = entry.value;
         if (content is DevFSFileContent && content.file is File) {
           inputs.add(globals.fs.file(content.file.path));
-          await (content.file as File).copy(file.path);
+          if (!await iconTreeShaker.subsetFont(
+            inputPath: content.file.path,
+            outputPath: file.path,
+            relativePath: entry.key,
+          )) {
+            await (content.file as File).copy(file.path);
+          }
         } else {
           await file.writeAsBytes(await entry.value.contentsAsBytes());
         }
@@ -65,11 +83,14 @@ class CopyAssets extends Target {
   String get name => 'copy_assets';
 
   @override
-  List<Target> get dependencies => const <Target>[];
+  List<Target> get dependencies => const <Target>[
+    KernelSnapshot(),
+  ];
 
   @override
   List<Source> get inputs => const <Source>[
     Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/assets.dart'),
+    ...IconTreeShaker.inputs,
   ];
 
   @override

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

@@ -14,6 +14,7 @@ import '../build_system.dart';
 import '../depfile.dart';
 import '../exceptions.dart';
 import 'assets.dart';
+import 'icon_tree_shaker.dart';
 
 /// The define to pass a [BuildMode].
 const String kBuildMode= 'BuildMode';
@@ -75,6 +76,7 @@ class CopyFlutterBundle extends Target {
     Source.artifact(Artifact.vmSnapshotData, mode: BuildMode.debug),
     Source.artifact(Artifact.isolateSnapshotData, mode: BuildMode.debug),
     Source.pattern('{BUILD_DIR}/app.dill'),
+    ...IconTreeShaker.inputs,
   ];
 
   @override

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

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:meta/meta.dart';
+import 'package:process/process.dart';
+
+import '../../artifacts.dart';
+import '../../base/common.dart';
+import '../../base/file_system.dart';
+import '../../base/io.dart';
+import '../../base/logger.dart';
+import '../../convert.dart';
+import '../../devfs.dart';
+import '../build_system.dart';
+import 'dart.dart';
+
+/// The build define controlling whether icon fonts should be stripped down to
+/// only the glyphs used by the application.
+const String kIconTreeShakerFlag = 'TreeShakeIcons';
+
+/// Whether icon font subsetting is enabled by default.
+const bool kIconTreeShakerEnabledDefault = false;
+
+List<Map<String, dynamic>> _getList(dynamic object, String errorMessage) {
+  try {
+    return (object as List<dynamic>).cast<Map<String, dynamic>>();
+  } on CastError catch (_) {
+    throw IconTreeShakerException._(errorMessage);
+  }
+}
+
+/// A class that wraps the functionality of the const finder package and the
+/// font subset utility to tree shake unused icons from fonts.
+class IconTreeShaker {
+  /// Creates a wrapper for icon font subsetting.
+  ///
+  /// The environment parameter must not be null.
+  ///
+  /// If the `fontManifest` parameter is null, [enabled] will return false since
+  /// there are no fonts to shake.
+  ///
+  /// The constructor will validate the environment and print a warning if
+  /// font subsetting has been requested in a debug build mode.
+  IconTreeShaker(
+    this._environment,
+    DevFSStringContent fontManifest, {
+    @required ProcessManager processManager,
+    @required Logger logger,
+    @required FileSystem fileSystem,
+    @required Artifacts artifacts,
+  }) : assert(_environment != null),
+       assert(processManager != null),
+       assert(logger != null),
+       assert(fileSystem != null),
+       assert(artifacts != null),
+       _processManager = processManager,
+       _logger = logger,
+       _fs = fileSystem,
+       _artifacts = artifacts,
+       _fontManifest = fontManifest?.string {
+    if (_environment.defines[kIconTreeShakerFlag] == 'true' &&
+        _environment.defines[kBuildMode] == 'debug') {
+      logger.printError('Font subetting is not supported in debug mode. The '
+                         '--tree-shake-icons flag will be ignored.');
+    }
+  }
+
+  /// The [Source] inputs that targets using this should depend on.
+  ///
+  /// See [Target.inputs].
+  static const List<Source> inputs = <Source>[
+    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/icon_tree_shaker.dart'),
+    Source.artifact(Artifact.constFinder),
+    Source.artifact(Artifact.fontSubset),
+  ];
+
+  final Environment _environment;
+  final String _fontManifest;
+  Map<String, _IconTreeShakerData> _iconData;
+
+  final ProcessManager _processManager;
+  final Logger _logger;
+  final FileSystem _fs;
+  final Artifacts _artifacts;
+
+  /// Whether font subsetting should be used for this [Environment].
+  bool get enabled => _fontManifest != null
+                   && _environment.defines[kIconTreeShakerFlag] == 'true'
+                   && _environment.defines[kBuildMode] != 'debug';
+
+  /// Fills the [_iconData] map.
+  Future<Map<String, _IconTreeShakerData>> _getIconData(Environment environment) async {
+    if (!enabled) {
+      return null;
+    }
+
+    final File appDill = environment.buildDir.childFile('app.dill');
+    if (!appDill.existsSync()) {
+      throw IconTreeShakerException._('Expected to find kernel file at ${appDill.path}, but no file found.');
+    }
+    final File constFinder = _fs.file(
+      _artifacts.getArtifactPath(Artifact.constFinder),
+    );
+    final File dart = _fs.file(
+      _artifacts.getArtifactPath(Artifact.engineDartBinary),
+    );
+
+    final Map<String, List<int>> iconData = await _findConstants(
+      dart,
+      constFinder,
+      appDill,
+    );
+    final Set<String> familyKeys = iconData.keys.toSet();
+
+    final Map<String, String> fonts = await _parseFontJson(
+      _fontManifest,
+      familyKeys,
+    );
+
+    if (fonts.length != iconData.length) {
+      throwToolExit('Expected to find fonts for ${iconData.keys}, but found '
+                    '${fonts.keys}. This usually means you are refering to '
+                    'font families in an IconData class but not including them '
+                    'in the assets section of your pubspec.yaml, are missing '
+                    'the package that would include them, or are missing '
+                    '"uses-material-design: true".');
+    }
+
+    final Map<String, _IconTreeShakerData> result = <String, _IconTreeShakerData>{};
+    for (final MapEntry<String, String> entry in fonts.entries) {
+      result[entry.value] = _IconTreeShakerData(
+        family: entry.key,
+        relativePath: entry.value,
+        codePoints: iconData[entry.key],
+      );
+    }
+    return result;
+  }
+
+  /// Calls font-subset, which transforms the `inputPath` font file to a
+  /// subsetted version at `outputPath`.
+  ///
+  /// The `relativePath` parameter
+  ///
+  /// All parameters are required.
+  ///
+  /// If [enabled] is false, or the relative path is not recognized as an icon
+  /// font used in the Flutter application, this returns false.
+  /// If the font-subset subprocess fails, it will [throwToolExit].
+  /// Otherwise, it will return true.
+  Future<bool> subsetFont({
+    @required String inputPath,
+    @required String outputPath,
+    @required String relativePath,
+  }) async {
+    if (!enabled) {
+      return false;
+    }
+
+    _iconData ??= await _getIconData(_environment);
+    assert(_iconData != null);
+
+    final _IconTreeShakerData iconTreeShakerData = _iconData[relativePath];
+    if (iconTreeShakerData == null) {
+      return false;
+    }
+
+    final File fontSubset = _fs.file(
+      _artifacts.getArtifactPath(Artifact.fontSubset),
+    );
+    if (!fontSubset.existsSync()) {
+      throw IconTreeShakerException._('The font-subset utility is missing. Run "flutter doctor".');
+    }
+
+    final List<String> cmd = <String>[
+      fontSubset.path,
+      outputPath,
+      inputPath,
+    ];
+    final String codePoints = iconTreeShakerData.codePoints.join(' ');
+    _logger.printTrace('Running font-subset: ${cmd.join(' ')}, '
+                       'using codepoints $codePoints');
+    final Process fontSubsetProcess = await _processManager.start(cmd);
+    try {
+      fontSubsetProcess.stdin.writeln(codePoints);
+      await fontSubsetProcess.stdin.flush();
+      await fontSubsetProcess.stdin.close();
+    } on Exception catch (_) {
+      // handled by checking the exit code.
+    } on OSError catch (_) {
+      // handled by checking the exit code.
+    }
+
+    final int code = await fontSubsetProcess.exitCode;
+    if (code != 0) {
+      _logger.printTrace(await utf8.decodeStream(fontSubsetProcess.stdout));
+      _logger.printError(await utf8.decodeStream(fontSubsetProcess.stderr));
+      throw IconTreeShakerException._('Font subsetting failed with exit code $code.');
+    }
+    return true;
+  }
+
+  /// Returns a map of { fontFamly: relativePath } pairs.
+  Future<Map<String, String>> _parseFontJson(
+    String fontManifestData,
+    Set<String> families,
+  ) async {
+    final Map<String, String> result = <String, String>{};
+    final List<Map<String, dynamic>> fontList = _getList(
+      json.decode(fontManifestData),
+      'FontManifest.json invalid: expected top level to be a list of objects.',
+    );
+
+    for (final Map<String, dynamic> map in fontList) {
+      if (map['family'] is! String) {
+        throw IconTreeShakerException._(
+          'FontManifest.json invalid: expected the family value to be a string, '
+          'got: ${map['family']}.');
+      }
+      final String familyKey = map['family'] as String;
+      if (!families.contains(familyKey)) {
+        continue;
+      }
+      final List<Map<String, dynamic>> fonts = _getList(
+        map['fonts'],
+        'FontManifest.json invalid: expected "fonts" to be a list of objects.',
+      );
+      if (fonts.length != 1) {
+        throw IconTreeShakerException._(
+          'This tool cannot process icon fonts with multiple fonts in a '
+          'single family.');
+      }
+      if (fonts.first['asset'] is! String) {
+        throw IconTreeShakerException._(
+          'FontManifest.json invalid: expected "asset" value to be a string, '
+          'got: ${map['assets']}.');
+      }
+      result[familyKey] = fonts.first['asset'] as String;
+    }
+    return result;
+  }
+
+  Future<Map<String, List<int>>> _findConstants(
+    File dart,
+    File constFinder,
+    File appDill,
+  ) async {
+    final List<String> cmd = <String>[
+      dart.path,
+      constFinder.path,
+      '--kernel-file', appDill.path,
+      '--class-library-uri', 'package:flutter/src/widgets/icon_data.dart',
+      '--class-name', 'IconData',
+    ];
+    _logger.printTrace('Running command: ${cmd.join(' ')}');
+    final ProcessResult constFinderProcessResult = await _processManager.run(cmd);
+
+    if (constFinderProcessResult.exitCode != 0) {
+      throw IconTreeShakerException._('ConstFinder failure: ${constFinderProcessResult.stderr}');
+    }
+    final dynamic jsonDecode = json.decode(constFinderProcessResult.stdout as String);
+    if (jsonDecode is! Map<String, dynamic>) {
+      throw IconTreeShakerException._(
+        'Invalid ConstFinder output: expected a top level JSON object, '
+        'got $jsonDecode.');
+    }
+    final Map<String, dynamic> constFinderMap = jsonDecode as Map<String, dynamic>;
+    final _ConstFinderResult constFinderResult = _ConstFinderResult(constFinderMap);
+    if (constFinderResult.hasNonConstantLocations) {
+      _logger.printError('This application cannot tree shake icons fonts. '
+                         'It has non-constant instances of IconData at the '
+                         'following locations:', emphasis: true);
+      for (final Map<String, dynamic> location in constFinderResult.nonConstantLocations) {
+        _logger.printError(
+          '- ${location['file']}:${location['line']}:${location['column']}',
+          indent: 2,
+          hangingIndent: 4,
+        );
+      }
+      throwToolExit('Avoid non-constant invocations of IconData or try to '
+                    'build again with --no-tree-shake-icons.');
+    }
+    return _parseConstFinderResult(constFinderResult);
+  }
+
+  Map<String, List<int>> _parseConstFinderResult(_ConstFinderResult consts) {
+    final Map<String, List<int>> result = <String, List<int>>{};
+    for (final Map<String, dynamic> iconDataMap in consts.constantInstances) {
+      if ((iconDataMap['fontPackage'] ?? '') is! String || // Null is ok here.
+           iconDataMap['fontFamily'] is! String ||
+           iconDataMap['codePoint'] is! int) {
+        throw IconTreeShakerException._(
+          'Invalid ConstFinder result. Expected "fontPackage" to be a String, '
+          '"fontFamily" to be a String, and "codePoint" to be an int, '
+          'got: $iconDataMap.');
+      }
+      final String package = iconDataMap['fontPackage'] as String;
+      final String family = iconDataMap['fontFamily'] as String;
+      final String key = package == null
+        ? family
+        : 'packages/$package/$family';
+      result[key] ??= <int>[];
+      result[key].add(iconDataMap['codePoint'] as int);
+    }
+    return result;
+  }
+}
+
+class _ConstFinderResult {
+  _ConstFinderResult(this.result);
+
+  final Map<String, dynamic> result;
+
+  List<Map<String, dynamic>> _constantInstances;
+  List<Map<String, dynamic>> get constantInstances {
+    _constantInstances ??= _getList(
+      result['constantInstances'],
+      'Invalid ConstFinder output: Expected "constInstances" to be a list of objects.',
+    );
+    return _constantInstances;
+  }
+
+  List<Map<String, dynamic>> _nonConstantLocations;
+  List<Map<String, dynamic>> get nonConstantLocations {
+    _nonConstantLocations ??= _getList(
+      result['nonConstantLocations'],
+      'Invalid ConstFinder output: Expected "nonConstLocations" to be a list ofobjects',
+    );
+    return _nonConstantLocations;
+  }
+
+  bool get hasNonConstantLocations => nonConstantLocations.isNotEmpty;
+}
+
+/// The font family name, relative path to font file, and list of code points
+/// the application is using.
+class _IconTreeShakerData {
+  /// All parameters are required.
+  const _IconTreeShakerData({
+    @required this.family,
+    @required this.relativePath,
+    @required this.codePoints,
+  }) : assert(family != null),
+       assert(relativePath != null),
+       assert(codePoints != null);
+
+  /// The font family name, e.g. "MaterialIcons".
+  final String family;
+
+  /// The relative path to the font file.
+  final String relativePath;
+
+  /// The list of code points for the font.
+  final List<int> codePoints;
+
+  @override
+  String toString() => 'FontSubsetData($family, $relativePath, $codePoints)';
+}
+
+class IconTreeShakerException implements Exception {
+  IconTreeShakerException._(this.message);
+
+  final String message;
+
+  @override
+  String toString() => 'FontSubset error: $message';
+}

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

@@ -11,6 +11,7 @@ import '../depfile.dart';
 import '../exceptions.dart';
 import 'assets.dart';
 import 'dart.dart';
+import 'icon_tree_shaker.dart';
 
 /// The only files/subdirectories we care out.
 const List<String> _kLinuxArtifacts = <String>[
@@ -119,6 +120,7 @@ class DebugBundleLinuxAssets extends Target {
     Source.pattern('{BUILD_DIR}/app.dill'),
     Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/linux.dart'),
     Source.pattern('{PROJECT_DIR}/pubspec.yaml'),
+    ...IconTreeShaker.inputs,
   ];
 
   @override

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

@@ -14,6 +14,7 @@ import '../depfile.dart';
 import '../exceptions.dart';
 import 'assets.dart';
 import 'dart.dart';
+import 'icon_tree_shaker.dart';
 
 const String _kOutputPrefix = '{OUTPUT_DIR}/FlutterMacOS.framework';
 
@@ -243,6 +244,7 @@ abstract class MacOSBundleFlutterAssets extends Target {
   @override
   List<Source> get inputs => const <Source>[
     Source.pattern('{BUILD_DIR}/App.framework/App'),
+    ...IconTreeShaker.inputs,
   ];
 
   @override

packages/flutter_tools/lib/src/bundle.dart

@@ -15,6 +15,7 @@ import 'build_info.dart';
 import 'build_system/build_system.dart';
 import 'build_system/depfile.dart';
 import 'build_system/targets/dart.dart';
+import 'build_system/targets/icon_tree_shaker.dart';
 import 'cache.dart';
 import 'dart/package_map.dart';
 import 'devfs.dart';
@@ -68,6 +69,7 @@ class BundleBuilder {
     List<String> extraGenSnapshotOptions = const <String>[],
     List<String> fileSystemRoots,
     String fileSystemScheme,
+    @required bool treeShakeIcons,
   }) async {
     mainPath ??= defaultMainPath;
     depfilePath ??= defaultDepfilePath;
@@ -83,6 +85,7 @@ class BundleBuilder {
       depfilePath: depfilePath,
       precompiled: precompiledSnapshot,
       trackWidgetCreation: trackWidgetCreation,
+      treeShakeIcons: treeShakeIcons,
     );
     // Work around for flutter_tester placing kernel artifacts in odd places.
     if (applicationKernelFilePath != null) {
@@ -107,6 +110,7 @@ Future<void> buildWithAssemble({
   @required String depfilePath,
   @required bool precompiled,
   bool trackWidgetCreation,
+  @required bool treeShakeIcons,
 }) async {
   // If the precompiled flag was not passed, force us into debug mode.
   buildMode = precompiled ? buildMode : BuildMode.debug;
@@ -121,6 +125,7 @@ Future<void> buildWithAssemble({
       kBuildMode: getNameForBuildMode(buildMode),
       kTargetPlatform: getNameForTargetPlatform(targetPlatform),
       kTrackWidgetCreation: trackWidgetCreation?.toString(),
+      kIconTreeShakerFlag: treeShakeIcons ? 'true' : null,
     },
   );
   final Target target = buildMode == BuildMode.debug

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

@@ -34,6 +34,7 @@ class BuildAarCommand extends BuildSubCommand {
         defaultsTo: true,
         help: 'Build a release version of the current project.',
       );
+    addTreeShakeIconsFlag();
     usesFlavorOption();
     usesBuildNumberOption();
     usesPubOption();
@@ -104,7 +105,7 @@ class BuildAarCommand extends BuildSubCommand {
     for (final String buildMode in const <String>['debug', 'profile', 'release']) {
       if (boolArg(buildMode)) {
         androidBuildInfo.add(AndroidBuildInfo(
-          BuildInfo(BuildMode.fromName(buildMode), stringArg('flavor')),
+          BuildInfo(BuildMode.fromName(buildMode), stringArg('flavor'), treeShakeIcons: boolArg('tree-shake-icons')),
           targetArchs: targetArchitectures,
         ));
       }

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

@@ -15,6 +15,7 @@ import 'build.dart';
 /// Builds AOT snapshots into platform specific library containers.
 class BuildAotCommand extends BuildSubCommand with TargetPlatformBasedDevelopmentArtifacts {
   BuildAotCommand({bool verboseHelp = false, this.aotBuilder}) {
+    addTreeShakeIconsFlag();
     usesTargetOption();
     addBuildModeFlags();
     usesPubOption();
@@ -88,6 +89,7 @@ class BuildAotCommand extends BuildSubCommand with TargetPlatformBasedDevelopmen
       extraFrontEndOptions: stringsArg(FlutterOptions.kExtraFrontEndOptions),
       extraGenSnapshotOptions: stringsArg(FlutterOptions.kExtraGenSnapshotOptions),
       dartDefines: dartDefines,
+      treeShakeIcons: boolArg('tree-shake-icons'),
     );
     return FlutterCommandResult.success();
   }

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

@@ -18,6 +18,7 @@ import 'build.dart';
 
 class BuildApkCommand extends BuildSubCommand {
   BuildApkCommand({bool verboseHelp = false}) {
+    addTreeShakeIconsFlag();
     usesTargetOption();
     addBuildModeFlags(verboseHelp: verboseHelp);
     usesFlavorOption();
@@ -25,7 +26,6 @@ class BuildApkCommand extends BuildSubCommand {
     usesBuildNumberOption();
     usesBuildNameOption();
     addShrinkingFlag();
-
     argParser
       ..addFlag('split-per-abi',
         negatable: false,

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

@@ -16,6 +16,7 @@ import 'build.dart';
 
 class BuildAppBundleCommand extends BuildSubCommand {
   BuildAppBundleCommand({bool verboseHelp = false}) {
+    addTreeShakeIconsFlag();
     usesTargetOption();
     addBuildModeFlags();
     usesFlavorOption();

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

@@ -16,6 +16,7 @@ import 'build.dart';
 
 class BuildBundleCommand extends BuildSubCommand {
   BuildBundleCommand({bool verboseHelp = false, this.bundleBuilder}) {
+    addTreeShakeIconsFlag();
     usesTargetOption();
     usesFilesystemOptions(hide: !verboseHelp);
     usesBuildNumberOption();
@@ -138,6 +139,7 @@ class BuildBundleCommand extends BuildSubCommand {
       extraGenSnapshotOptions: stringsArg(FlutterOptions.kExtraGenSnapshotOptions),
       fileSystemScheme: stringArg('filesystem-scheme'),
       fileSystemRoots: stringsArg('filesystem-root'),
+      treeShakeIcons: boolArg('tree-shake-icons'),
     );
     return FlutterCommandResult.success();
   }

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

@@ -17,6 +17,7 @@ import 'build.dart';
 /// A command to build a Fuchsia target.
 class BuildFuchsiaCommand extends BuildSubCommand {
   BuildFuchsiaCommand({bool verboseHelp = false}) {
+    addTreeShakeIconsFlag();
     usesTargetOption();
     addBuildModeFlags(verboseHelp: verboseHelp);
     argParser.addOption(

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

@@ -18,6 +18,7 @@ import 'build.dart';
 /// .ipas, see https://flutter.dev/docs/deployment/ios.
 class BuildIOSCommand extends BuildSubCommand {
   BuildIOSCommand() {
+    addTreeShakeIconsFlag();
     addBuildModeFlags(defaultToRelease: false);
     usesTargetOption();
     usesFlavorOption();

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

@@ -44,6 +44,7 @@ class BuildIOSFrameworkCommand extends BuildSubCommand {
        _bundleBuilder = bundleBuilder,
        _cache = cache,
        _platform = platform {
+    addTreeShakeIconsFlag();
     usesTargetOption();
     usesFlavorOption();
     usesPubOption();
@@ -361,6 +362,7 @@ end
         mainPath: globals.fs.path.absolute(targetFile),
         assetDirPath: destinationAppFrameworkDirectory.childDirectory('flutter_assets').path,
         precompiledSnapshot: mode != BuildMode.debug,
+        treeShakeIcons: boolArg('tree-shake-icons')
       );
     } finally {
       status.stop();
@@ -426,6 +428,7 @@ end
         reportTimings: false,
         iosBuildArchs: <DarwinArch>[DarwinArch.armv7, DarwinArch.arm64],
         dartDefines: dartDefines,
+        treeShakeIcons: boolArg('tree-shake-icons'),
       );
     } finally {
       status.stop();

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

@@ -17,6 +17,7 @@ import 'build.dart';
 /// A command to build a linux desktop target through a build shell script.
 class BuildLinuxCommand extends BuildSubCommand {
   BuildLinuxCommand() {
+    addTreeShakeIconsFlag();
     addBuildModeFlags();
     usesTargetOption();
   }

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

@@ -17,6 +17,7 @@ import 'build.dart';
 /// A command to build a macOS desktop target through a build shell script.
 class BuildMacosCommand extends BuildSubCommand {
   BuildMacosCommand() {
+    addTreeShakeIconsFlag();
     usesTargetOption();
     addBuildModeFlags();
   }

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

@@ -15,6 +15,7 @@ import 'build.dart';
 
 class BuildWebCommand extends BuildSubCommand {
   BuildWebCommand() {
+    addTreeShakeIconsFlag();
     usesTargetOption();
     usesPubOption();
     addBuildModeFlags(excludeDebug: true);

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

@@ -17,6 +17,7 @@ import 'build.dart';
 /// A command to build a windows desktop target through a build shell script.
 class BuildWindowsCommand extends BuildSubCommand {
   BuildWindowsCommand() {
+    addTreeShakeIconsFlag();
     addBuildModeFlags();
     usesTargetOption();
   }

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

@@ -209,7 +209,6 @@ Future<XcodeBuildResult> buildXcodeProject({
   bool buildForDevice,
   DarwinArch activeArch,
   bool codesign = true,
-
 }) async {
   if (!upgradePbxProjWithFlutterAssets(app.project)) {
     return XcodeBuildResult(success: false);

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

@@ -428,7 +428,8 @@ class IOSSimulator extends Device {
     final BuildInfo debugBuildInfo = BuildInfo(BuildMode.debug, buildInfo.flavor,
         trackWidgetCreation: buildInfo.trackWidgetCreation,
         extraFrontEndOptions: buildInfo.extraFrontEndOptions,
-        extraGenSnapshotOptions: buildInfo.extraGenSnapshotOptions);
+        extraGenSnapshotOptions: buildInfo.extraGenSnapshotOptions,
+        treeShakeIcons: buildInfo.treeShakeIcons);
 
     final XcodeBuildResult buildResult = await buildXcodeProject(
       app: app,
@@ -460,6 +461,7 @@ class IOSSimulator extends Device {
       precompiledSnapshot: false,
       buildMode: buildInfo.mode,
       trackWidgetCreation: buildInfo.trackWidgetCreation,
+      treeShakeIcons: false,
     );
   }
 

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

@@ -216,6 +216,10 @@ List<String> _xcodeBuildSettingsLines({
     xcodeBuildSettings.add('TRACK_WIDGET_CREATION=true');
   }
 
+  if (buildInfo.treeShakeIcons) {
+    xcodeBuildSettings.add('TREE_SHAKE_ICONS=true');
+  }
+
   return xcodeBuildSettings;
 }
 

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

@@ -85,6 +85,8 @@ Future<void> buildMacOS({
       'OBJROOT=${globals.fs.path.join(flutterBuildDir.absolute.path, 'Build', 'Intermediates.noindex')}',
       'SYMROOT=${globals.fs.path.join(flutterBuildDir.absolute.path, 'Build', 'Products')}',
       'COMPILER_INDEX_STORE_ENABLE=NO',
+      if (buildInfo.treeShakeIcons)
+        'TREE_SHAKE_ICONS=true',
       ...environmentVariablesAsXcodeBuildSettings(globals.platform)
     ], trace: true);
   } finally {

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

@@ -20,6 +20,7 @@ import '../base/time.dart';
 import '../base/user_messages.dart';
 import '../base/utils.dart';
 import '../build_info.dart';
+import '../build_system/targets/icon_tree_shaker.dart' show kIconTreeShakerEnabledDefault;
 import '../bundle.dart' as bundle;
 import '../cache.dart';
 import '../dart/package_map.dart';
@@ -365,6 +366,14 @@ abstract class FlutterCommand extends Command<void> {
       help: 'Build a JIT release version of your app${defaultToRelease ? ' (default mode)' : ''}.');
   }
 
+  void addTreeShakeIconsFlag() {
+    argParser.addFlag('tree-shake-icons',
+      negatable: true,
+      defaultsTo: kIconTreeShakerEnabledDefault,
+      help: 'Tree shake icon fonts so that only glyphs used by the application remain.',
+    );
+  }
+
   void addShrinkingFlag() {
     argParser.addFlag('shrink',
       negatable: true,
@@ -490,6 +499,9 @@ abstract class FlutterCommand extends Command<void> {
       buildName: argParser.options.containsKey('build-name')
           ? stringArg('build-name')
           : null,
+      treeShakeIcons: argParser.options.containsKey('tree-shake-icons')
+          ? boolArg('tree-shake-icons')
+          : kIconTreeShakerEnabledDefault,
     );
   }
 

packages/flutter_tools/lib/src/tester/flutter_tester.dart

@@ -151,6 +151,7 @@ class FlutterTesterDevice extends Device {
       precompiledSnapshot: false,
       trackWidgetCreation: buildInfo.trackWidgetCreation,
       platform: getTargetPlatformForName(getNameForHostPlatform(getCurrentHostPlatform())),
+      treeShakeIcons: buildInfo.treeShakeIcons,
     );
     command.add('--flutter-assets-dir=$assetDirPath');
 

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

@@ -52,6 +52,8 @@ Future<void> buildWeb(
         kHasWebPlugins: hasWebPlugins.toString(),
         kDartDefines: jsonEncode(dartDefines),
         kCspMode: csp.toString(),
+        // TODO(dnfield): Enable font subset. We need to get a kernel file to do
+        // that. https://github.com/flutter/flutter/issues/49730
       },
     ));
     if (!result.success) {

packages/flutter_tools/pubspec.yaml

@@ -5,7 +5,7 @@ author: Flutter Authors <flutter-dev@googlegroups.com>
 
 environment:
   # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
-  sdk: ">=2.2.2 <3.0.0"
+  sdk: ">=2.7.0 <3.0.0"
 
 dependencies:
   # To update these, use "flutter update-packages --force-upgrade".

packages/flutter_tools/test/commands.shard/permeable/build_bundle_test.dart

@@ -7,6 +7,7 @@ import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/targets/dart.dart';
+import 'package:flutter_tools/src/build_system/targets/icon_tree_shaker.dart';
 import 'package:flutter_tools/src/bundle.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/build_bundle.dart';
@@ -47,6 +48,7 @@ void main() {
         extraGenSnapshotOptions: anyNamed('extraGenSnapshotOptions'),
         fileSystemRoots: anyNamed('fileSystemRoots'),
         fileSystemScheme: anyNamed('fileSystemScheme'),
+        treeShakeIcons: anyNamed('treeShakeIcons'),
       ),
     ).thenAnswer((_) => Future<void>.value());
   });
@@ -217,6 +219,7 @@ void main() {
         kBuildMode: 'debug',
         kTargetPlatform: 'android-arm',
         kTrackWidgetCreation: 'true',
+        kIconTreeShakerFlag: null,
       });
 
       return BuildResult(success: true);

packages/flutter_tools/test/general.shard/android/android_device_test.dart

@@ -101,7 +101,7 @@ void main() {
           mockApk,
           prebuiltApplication: true,
           debuggingOptions: DebuggingOptions.disabled(
-            const BuildInfo(BuildMode.release, null),
+            const BuildInfo(BuildMode.release, null, treeShakeIcons: false),
             cacheSkSL: true,
           ),
           platformArgs: <String, dynamic>{},
@@ -153,7 +153,7 @@ void main() {
           mockApk,
           prebuiltApplication: true,
           debuggingOptions: DebuggingOptions.disabled(
-            const BuildInfo(BuildMode.release, null),
+            const BuildInfo(BuildMode.release, null, treeShakeIcons: false),
           ),
           platformArgs: <String, dynamic>{},
         );

packages/flutter_tools/test/general.shard/android/gradle_test.dart

@@ -98,33 +98,33 @@ void main() {
   group('gradle tasks', () {
     test('assemble release', () {
       expect(
-        getAssembleTaskFor(const BuildInfo(BuildMode.release, null)),
+        getAssembleTaskFor(const BuildInfo(BuildMode.release, null, treeShakeIcons: false)),
         equals('assembleRelease'),
       );
       expect(
-        getAssembleTaskFor(const BuildInfo(BuildMode.release, 'flavorFoo')),
+        getAssembleTaskFor(const BuildInfo(BuildMode.release, 'flavorFoo', treeShakeIcons: false)),
         equals('assembleFlavorFooRelease'),
       );
     });
 
     test('assemble debug', () {
       expect(
-        getAssembleTaskFor(const BuildInfo(BuildMode.debug, null)),
+        getAssembleTaskFor(const BuildInfo(BuildMode.debug, null, treeShakeIcons: false)),
         equals('assembleDebug'),
       );
       expect(
-        getAssembleTaskFor(const BuildInfo(BuildMode.debug, 'flavorFoo')),
+        getAssembleTaskFor(const BuildInfo(BuildMode.debug, 'flavorFoo', treeShakeIcons: false)),
         equals('assembleFlavorFooDebug'),
       );
     });
 
     test('assemble profile', () {
       expect(
-        getAssembleTaskFor(const BuildInfo(BuildMode.profile, null)),
+        getAssembleTaskFor(const BuildInfo(BuildMode.profile, null, treeShakeIcons: false)),
         equals('assembleProfile'),
       );
       expect(
-        getAssembleTaskFor(const BuildInfo(BuildMode.profile, 'flavorFoo')),
+        getAssembleTaskFor(const BuildInfo(BuildMode.profile, 'flavorFoo', treeShakeIcons: false)),
         equals('assembleFlavorFooProfile'),
       );
     });
@@ -135,7 +135,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor contains underscores in release mode', () {
       final FlutterProject project = generateFakeAppBundle('foo_barRelease', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, 'foo_bar'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, 'foo_bar', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'foo_barRelease', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -145,7 +145,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor doesn\'t contain underscores in release mode', () {
       final FlutterProject project = generateFakeAppBundle('fooRelease', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, 'foo'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, 'foo', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'fooRelease', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -155,7 +155,7 @@ void main() {
 
     testUsingContext('Finds app bundle when no flavor is used in release mode', () {
       final FlutterProject project = generateFakeAppBundle('release', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, null));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, null, treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'release', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -165,7 +165,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor contains underscores in debug mode', () {
       final FlutterProject project = generateFakeAppBundle('foo_barDebug', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, 'foo_bar'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, 'foo_bar', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'foo_barDebug', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -175,7 +175,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor doesn\'t contain underscores in debug mode', () {
       final FlutterProject project = generateFakeAppBundle('fooDebug', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, 'foo'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, 'foo', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'fooDebug', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -185,7 +185,7 @@ void main() {
 
     testUsingContext('Finds app bundle when no flavor is used in debug mode', () {
       final FlutterProject project = generateFakeAppBundle('debug', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, null));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, null, treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'debug', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -195,7 +195,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor contains underscores in profile mode', () {
       final FlutterProject project = generateFakeAppBundle('foo_barProfile', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, 'foo_bar'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, 'foo_bar', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'foo_barProfile', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -205,7 +205,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor doesn\'t contain underscores in profile mode', () {
       final FlutterProject project = generateFakeAppBundle('fooProfile', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, 'foo'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, 'foo', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'fooProfile', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -215,7 +215,7 @@ void main() {
 
     testUsingContext('Finds app bundle when no flavor is used in profile mode', () {
       final FlutterProject project = generateFakeAppBundle('profile', 'app.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, null));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, null, treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'profile', 'app.aab'));
     }, overrides: <Type, Generator>{
@@ -225,7 +225,7 @@ void main() {
 
     testUsingContext('Finds app bundle in release mode - Gradle 3.5', () {
       final FlutterProject project = generateFakeAppBundle('release', 'app-release.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, null));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, null, treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'release', 'app-release.aab'));
     }, overrides: <Type, Generator>{
@@ -235,7 +235,7 @@ void main() {
 
     testUsingContext('Finds app bundle in profile mode - Gradle 3.5', () {
       final FlutterProject project = generateFakeAppBundle('profile', 'app-profile.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, null));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, null, treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'profile', 'app-profile.aab'));
     }, overrides: <Type, Generator>{
@@ -245,7 +245,7 @@ void main() {
 
     testUsingContext('Finds app bundle in debug mode - Gradle 3.5', () {
       final FlutterProject project = generateFakeAppBundle('debug', 'app-debug.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, null));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, null, treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'debug', 'app-debug.aab'));
     }, overrides: <Type, Generator>{
@@ -255,7 +255,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor contains underscores in release mode - Gradle 3.5', () {
       final FlutterProject project = generateFakeAppBundle('foo_barRelease', 'app-foo_bar-release.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, 'foo_bar'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.release, 'foo_bar', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'foo_barRelease', 'app-foo_bar-release.aab'));
     }, overrides: <Type, Generator>{
@@ -265,7 +265,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor contains underscores in profile mode - Gradle 3.5', () {
       final FlutterProject project = generateFakeAppBundle('foo_barProfile', 'app-foo_bar-profile.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, 'foo_bar'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.profile, 'foo_bar', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant', 'app', 'outputs', 'bundle', 'foo_barProfile', 'app-foo_bar-profile.aab'));
     }, overrides: <Type, Generator>{
@@ -275,7 +275,7 @@ void main() {
 
     testUsingContext('Finds app bundle when flavor contains underscores in debug mode - Gradle 3.5', () {
       final FlutterProject project = generateFakeAppBundle('foo_barDebug', 'app-foo_bar-debug.aab');
-      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, 'foo_bar'));
+      final File bundle = findBundleFile(project, const BuildInfo(BuildMode.debug, 'foo_bar', treeShakeIcons: false));
       expect(bundle, isNotNull);
       expect(bundle.path, globals.fs.path.join('irrelevant','app', 'outputs', 'bundle', 'foo_barDebug', 'app-foo_bar-debug.aab'));
     }, overrides: <Type, Generator>{
@@ -287,7 +287,7 @@ void main() {
       final FlutterProject project = FlutterProject.current();
       expect(
         () {
-          findBundleFile(project, const BuildInfo(BuildMode.debug, 'foo_bar'));
+          findBundleFile(project, const BuildInfo(BuildMode.debug, 'foo_bar', treeShakeIcons: false));
         },
         throwsToolExit(
           message:
@@ -329,7 +329,7 @@ void main() {
 
       final Iterable<File> apks = findApkFiles(
         project,
-        const AndroidBuildInfo(BuildInfo(BuildMode.release, '')),
+        const AndroidBuildInfo(BuildInfo(BuildMode.release, '', treeShakeIcons: false)),
       );
       expect(apks.isNotEmpty, isTrue);
       expect(apks.first.path, equals(globals.fs.path.join('irrelevant', 'app', 'outputs', 'apk', 'release', 'app-release.apk')));
@@ -352,7 +352,7 @@ void main() {
 
       final Iterable<File> apks = findApkFiles(
         project,
-        const AndroidBuildInfo(BuildInfo(BuildMode.release, 'flavor1')),
+        const AndroidBuildInfo(BuildInfo(BuildMode.release, 'flavor1', treeShakeIcons: false)),
       );
       expect(apks.isNotEmpty, isTrue);
       expect(apks.first.path, equals(globals.fs.path.join('irrelevant', 'app', 'outputs', 'apk', 'release', 'app-flavor1-release.apk')));
@@ -375,7 +375,7 @@ void main() {
 
       final Iterable<File> apks = findApkFiles(
         project,
-        const AndroidBuildInfo(BuildInfo(BuildMode.release, 'flavor1')),
+        const AndroidBuildInfo(BuildInfo(BuildMode.release, 'flavor1', treeShakeIcons: false)),
       );
       expect(apks.isNotEmpty, isTrue);
       expect(apks.first.path, equals(globals.fs.path.join('irrelevant', 'app', 'outputs', 'apk', 'flavor1', 'release', 'app-flavor1-release.apk')));
@@ -390,7 +390,7 @@ void main() {
         () {
           findApkFiles(
             project,
-            const AndroidBuildInfo(BuildInfo(BuildMode.debug, 'foo_bar')),
+            const AndroidBuildInfo(BuildInfo(BuildMode.debug, 'foo_bar', treeShakeIcons: false)),
           );
         },
         throwsToolExit(
@@ -604,7 +604,7 @@ dependencies:
 flutter:
 ''';
 
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, treeShakeIcons: false);
       await checkBuildVersion(
         manifest: manifest,
         buildInfo: buildInfo,
@@ -622,7 +622,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, treeShakeIcons: false);
       await checkBuildVersion(
         manifest: manifest,
         buildInfo: buildInfo,
@@ -640,7 +640,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', treeShakeIcons: false);
       await checkBuildVersion(
         manifest: manifest,
         buildInfo: buildInfo,
@@ -658,7 +658,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildNumber: '3');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildNumber: '3', treeShakeIcons: false);
       await checkBuildVersion(
         manifest: manifest,
         buildInfo: buildInfo,
@@ -676,7 +676,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3', treeShakeIcons: false);
       await checkBuildVersion(
         manifest: manifest,
         buildInfo: buildInfo,
@@ -694,7 +694,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3', treeShakeIcons: false);
       await checkBuildVersion(
         manifest: manifest,
         buildInfo: buildInfo,
@@ -711,7 +711,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3', treeShakeIcons: false);
       await checkBuildVersion(
         manifest: manifest,
         buildInfo: buildInfo,
@@ -730,19 +730,19 @@ flutter:
 ''';
       await checkBuildVersion(
         manifest: manifest,
-        buildInfo: const BuildInfo(BuildMode.release, null, buildName: null, buildNumber: null),
+        buildInfo: const BuildInfo(BuildMode.release, null, buildName: null, buildNumber: null, treeShakeIcons: false),
         expectedBuildName: null,
         expectedBuildNumber: null,
       );
       await checkBuildVersion(
         manifest: manifest,
-        buildInfo: const BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3'),
+        buildInfo: const BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3', treeShakeIcons: false),
         expectedBuildName: '1.0.2',
         expectedBuildNumber: '3',
       );
       await checkBuildVersion(
         manifest: manifest,
-        buildInfo: const BuildInfo(BuildMode.release, null, buildName: '1.0.3', buildNumber: '4'),
+        buildInfo: const BuildInfo(BuildMode.release, null, buildName: '1.0.3', buildNumber: '4', treeShakeIcons: false),
         expectedBuildName: '1.0.3',
         expectedBuildNumber: '4',
       );
@@ -756,7 +756,7 @@ flutter:
       // Values get unset.
       await checkBuildVersion(
         manifest: manifest,
-        buildInfo: const BuildInfo(BuildMode.release, null, buildName: null, buildNumber: null),
+        buildInfo: const BuildInfo(BuildMode.release, null, buildName: null, buildNumber: null, treeShakeIcons: false),
         expectedBuildName: null,
         expectedBuildNumber: null,
       );
@@ -1125,6 +1125,7 @@ plugin1=${plugin1.path}
             BuildInfo(
               BuildMode.release,
               null,
+              treeShakeIcons: false,
             ),
           ),
           target: 'lib/main.dart',
@@ -1204,6 +1205,7 @@ plugin1=${plugin1.path}
             BuildInfo(
               BuildMode.release,
               null,
+              treeShakeIcons: false,
             ),
           ),
           target: 'lib/main.dart',
@@ -1279,6 +1281,7 @@ plugin1=${plugin1.path}
             BuildInfo(
               BuildMode.release,
               null,
+              treeShakeIcons: false,
             ),
           ),
           target: 'lib/main.dart',
@@ -1351,6 +1354,7 @@ plugin1=${plugin1.path}
             BuildInfo(
               BuildMode.release,
               null,
+              treeShakeIcons: false,
             ),
           ),
           target: 'lib/main.dart',
@@ -1418,6 +1422,7 @@ plugin1=${plugin1.path}
           BuildInfo(
             BuildMode.release,
             null,
+            treeShakeIcons: false,
           ),
         ),
         target: 'lib/main.dart',
@@ -1491,6 +1496,7 @@ plugin1=${plugin1.path}
             BuildInfo(
               BuildMode.release,
               null,
+              treeShakeIcons: false,
             ),
           ),
           target: 'lib/main.dart',
@@ -1582,6 +1588,7 @@ plugin1=${plugin1.path}
           BuildInfo(
             BuildMode.release,
             null,
+            treeShakeIcons: false,
           ),
         ),
         target: 'lib/main.dart',
@@ -1630,7 +1637,7 @@ plugin1=${plugin1.path}
       fileSystem.directory('build/outputs/repo').createSync(recursive: true);
 
       await buildGradleAar(
-        androidBuildInfo: const AndroidBuildInfo(BuildInfo(BuildMode.release, null)),
+        androidBuildInfo: const AndroidBuildInfo(BuildInfo(BuildMode.release, null, treeShakeIcons: false)),
         project: FlutterProject.current(),
         outputDirectory: fileSystem.directory('build/'),
         target: '',
@@ -1715,6 +1722,7 @@ plugin1=${plugin1.path}
             BuildInfo(
               BuildMode.release,
               null,
+              treeShakeIcons: false,
             ),
           ),
           target: 'lib/main.dart',
@@ -1801,7 +1809,7 @@ plugin1=${plugin1.path}
       when(fileSystemUtils.copyDirectorySync(any, any)).thenReturn(null);
 
       await buildGradleAar(
-        androidBuildInfo: const AndroidBuildInfo(BuildInfo(BuildMode.release, null)),
+        androidBuildInfo: const AndroidBuildInfo(BuildInfo(BuildMode.release, null, treeShakeIcons: false)),
         project: FlutterProject.current(),
         outputDirectory: fileSystem.directory('build/'),
         target: '',

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

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:io';
-
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/targets/assets.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
@@ -12,7 +10,6 @@ import '../../../src/common.dart';
 import '../../../src/testbed.dart';
 
 void main() {
-  const BuildSystem buildSystem = BuildSystem();
   Environment environment;
   Testbed testbed;
 
@@ -21,6 +18,7 @@ void main() {
       environment = Environment.test(
         globals.fs.currentDirectory,
       );
+      globals.fs.file(environment.buildDir.childFile('app.dill')).createSync(recursive: true);
       globals.fs.file(globals.fs.path.join('packages', 'flutter_tools', 'lib', 'src',
           'build_system', 'targets', 'assets.dart'))
         ..createSync(recursive: true);
@@ -44,7 +42,7 @@ flutter:
   });
 
   test('Copies files to correct asset directory', () => testbed.run(() async {
-    await buildSystem.build(const CopyAssets(), environment);
+    await const CopyAssets().build(environment);
 
     expect(globals.fs.file(globals.fs.path.join(environment.buildDir.path, 'flutter_assets', 'AssetManifest.json')).existsSync(), true);
     expect(globals.fs.file(globals.fs.path.join(environment.buildDir.path, 'flutter_assets', 'FontManifest.json')).existsSync(), true);
@@ -55,24 +53,6 @@ flutter:
     expect(globals.fs.file(globals.fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/wildcard/%23bar.png')).existsSync(), true);
   }));
 
-  test('Does not leave stale files in build directory', () => testbed.run(() async {
-    await buildSystem.build(const CopyAssets(), environment);
-
-    expect(globals.fs.file(globals.fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), true);
-    // Modify manifest to remove asset.
-    globals.fs.file('pubspec.yaml')
-      ..createSync()
-      ..writeAsStringSync('''
-name: example
-
-flutter:
-''');
-    await buildSystem.build(const CopyAssets(), environment);
-
-    // See https://github.com/flutter/flutter/issues/35293
-    expect(globals.fs.file(globals.fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), false);
-  }), skip: Platform.isWindows); // See https://github.com/google/file.dart/issues/131
-
   test('FlutterPlugins updates required files as needed', () => testbed.run(() async {
     globals.fs.file('pubspec.yaml')
       ..writeAsStringSync('name: foo\ndependencies:\n  foo: any\n');

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

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:file/memory.dart';
+import 'package:flutter_tools/src/artifacts.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/base/terminal.dart';
+import 'package:flutter_tools/src/build_system/build_system.dart';
+import 'package:flutter_tools/src/build_system/targets/dart.dart';
+import 'package:flutter_tools/src/build_system/targets/icon_tree_shaker.dart';
+import 'package:flutter_tools/src/devfs.dart';
+import 'package:meta/meta.dart';
+import 'package:mockito/mockito.dart';
+import 'package:platform/platform.dart';
+
+import '../../../src/common.dart';
+import '../../../src/context.dart';
+import '../../../src/mocks.dart' as mocks;
+
+final Platform _kNoAnsiPlatform =
+    FakePlatform.fromPlatform(const LocalPlatform())
+      ..stdoutSupportsAnsi = false;
+
+void main() {
+  BufferLogger logger;
+  MemoryFileSystem fs;
+  MockProcessManager mockProcessManager;
+  MockProcess fontSubsetProcess;
+  MockArtifacts mockArtifacts;
+  DevFSStringContent fontManifestContent;
+
+  const String dartPath = '/flutter/dart';
+  const String constFinderPath = '/flutter/const_finder.snapshot.dart';
+  const String fontSubsetPath = '/flutter/font-subset';
+
+  const String inputPath = '/input/fonts/MaterialIcons-Regular.ttf';
+  const String outputPath = '/output/fonts/MaterialIcons-Regular.ttf';
+  const String relativePath = 'fonts/MaterialIcons-Regular.ttf';
+
+  List<String> getConstFinderArgs(String appDillPath) => <String>[
+    dartPath,
+    constFinderPath,
+    '--kernel-file', appDillPath,
+    '--class-library-uri', 'package:flutter/src/widgets/icon_data.dart',
+    '--class-name', 'IconData',
+  ];
+
+  const List<String> fontSubsetArgs = <String>[
+    fontSubsetPath,
+    outputPath,
+    inputPath,
+  ];
+
+  void _addConstFinderInvocation(
+    String appDillPath, {
+    int exitCode = 0,
+    String stdout = '',
+    String stderr = '',
+  }) {
+    when(mockProcessManager.run(getConstFinderArgs(appDillPath))).thenAnswer((_) async {
+      return ProcessResult(0, exitCode, stdout, stderr);
+    });
+  }
+
+  void _resetFontSubsetInvocation({
+    int exitCode = 0,
+    String stdout = '',
+    String stderr = '',
+    @required mocks.CompleterIOSink stdinSink,
+  }) {
+    assert(stdinSink != null);
+    stdinSink.writes.clear();
+    when(fontSubsetProcess.exitCode).thenAnswer((_) async => exitCode);
+    when(fontSubsetProcess.stdout).thenAnswer((_) => Stream<List<int>>.fromIterable(<List<int>>[utf8.encode(stdout)]));
+    when(fontSubsetProcess.stderr).thenAnswer((_) => Stream<List<int>>.fromIterable(<List<int>>[utf8.encode(stderr)]));
+    when(fontSubsetProcess.stdin).thenReturn(stdinSink);
+    when(mockProcessManager.start(fontSubsetArgs)).thenAnswer((_) async {
+      return fontSubsetProcess;
+    });
+  }
+
+  setUp(() {
+    fontManifestContent = DevFSStringContent(validFontManifestJson);
+
+    mockProcessManager = MockProcessManager();
+    fontSubsetProcess = MockProcess();
+    mockArtifacts = MockArtifacts();
+
+    fs = MemoryFileSystem();
+    logger = BufferLogger(
+      terminal: AnsiTerminal(
+        stdio: mocks.MockStdio(),
+        platform: _kNoAnsiPlatform,
+      ),
+      outputPreferences: OutputPreferences.test(showColor: false),
+    );
+
+    fs.file(constFinderPath).createSync(recursive: true);
+    fs.file(dartPath).createSync(recursive: true);
+    fs.file(fontSubsetPath).createSync(recursive: true);
+    when(mockArtifacts.getArtifactPath(Artifact.constFinder)).thenReturn(constFinderPath);
+    when(mockArtifacts.getArtifactPath(Artifact.fontSubset)).thenReturn(fontSubsetPath);
+    when(mockArtifacts.getArtifactPath(Artifact.engineDartBinary)).thenReturn(dartPath);
+  });
+
+  Environment _createEnvironment(Map<String, String> defines) {
+    return Environment.test(
+      fs.directory('/icon_test')..createSync(recursive: true),
+      defines: defines,
+    );
+  }
+
+  testWithoutContext('Prints error in debug mode environment', () async {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'debug',
+    });
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    expect(
+      logger.errorText,
+      'Font subetting is not supported in debug mode. The --tree-shake-icons flag will be ignored.\n',
+    );
+    expect(iconTreeShaker.enabled, false);
+
+    final bool subsets = await iconTreeShaker.subsetFont(
+      inputPath: inputPath,
+      outputPath: outputPath,
+      relativePath: relativePath,
+    );
+    expect(subsets, false);
+
+    verifyNever(mockProcessManager.run(any));
+    verifyNever(mockProcessManager.start(any));
+  });
+
+  testWithoutContext('Does not get enabled without font manifest', () {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      null,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    expect(
+      logger.errorText,
+      isEmpty,
+    );
+    expect(iconTreeShaker.enabled, false);
+    verifyNever(mockProcessManager.run(any));
+    verifyNever(mockProcessManager.start(any));
+  });
+
+  testWithoutContext('Gets enabled', () {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    expect(
+      logger.errorText,
+      isEmpty,
+    );
+    expect(iconTreeShaker.enabled, true);
+    verifyNever(mockProcessManager.run(any));
+    verifyNever(mockProcessManager.start(any));
+  });
+
+  test('No app.dill throws exception', () async {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    expect(
+      () => iconTreeShaker.subsetFont(
+        inputPath: inputPath,
+        outputPath: outputPath,
+        relativePath: relativePath,
+      ),
+      throwsA(isA<IconTreeShakerException>()),
+    );
+  });
+
+  testWithoutContext('The happy path', () async {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+    final File appDill = environment.buildDir.childFile('app.dill')..createSync(recursive: true);
+    fs.file(inputPath).createSync(recursive: true);
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    final mocks.CompleterIOSink stdinSink = mocks.CompleterIOSink();
+    _addConstFinderInvocation(appDill.path, stdout: validConstFinderResult);
+    _resetFontSubsetInvocation(stdinSink: stdinSink);
+
+    bool subsetted = await iconTreeShaker.subsetFont(
+      inputPath: inputPath,
+      outputPath: outputPath,
+      relativePath: relativePath,
+    );
+    expect(stdinSink.writes, <List<int>>[utf8.encode('59470\n')]);
+    _resetFontSubsetInvocation(stdinSink: stdinSink);
+
+    expect(subsetted, true);
+    subsetted = await iconTreeShaker.subsetFont(
+      inputPath: inputPath,
+      outputPath: outputPath,
+      relativePath: relativePath,
+    );
+    expect(subsetted, true);
+    expect(stdinSink.writes, <List<int>>[utf8.encode('59470\n')]);
+
+    verify(mockProcessManager.run(getConstFinderArgs(appDill.path))).called(1);
+    verify(mockProcessManager.start(fontSubsetArgs)).called(2);
+  });
+
+  testWithoutContext('Non-constant instances', () async {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+    final File appDill = environment.buildDir.childFile('app.dill')..createSync(recursive: true);
+    fs.file(inputPath).createSync(recursive: true);
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    _addConstFinderInvocation(appDill.path, stdout: constFinderResultWithInvalid);
+
+    expect(
+      iconTreeShaker.subsetFont(
+        inputPath: inputPath,
+        outputPath: outputPath,
+        relativePath: relativePath,
+      ),
+      throwsToolExit(
+        message: 'Avoid non-constant invocations of IconData or try to build again with --no-tree-shake-icons.',
+      ),
+    );
+
+    verify(mockProcessManager.run(getConstFinderArgs(appDill.path))).called(1);
+    verifyNever(mockProcessManager.start(fontSubsetArgs));
+  });
+
+  testWithoutContext('Non-zero font-subset exit code', () async {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+    final File appDill = environment.buildDir.childFile('app.dill')..createSync(recursive: true);
+    fs.file(inputPath).createSync(recursive: true);
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    final mocks.CompleterIOSink stdinSink = mocks.CompleterIOSink();
+    _addConstFinderInvocation(appDill.path, stdout: validConstFinderResult);
+    _resetFontSubsetInvocation(exitCode: -1, stdinSink: stdinSink);
+
+    expect(
+      iconTreeShaker.subsetFont(
+        inputPath: inputPath,
+        outputPath: outputPath,
+        relativePath: relativePath,
+      ),
+      throwsA(isA<IconTreeShakerException>()),
+    );
+
+    verify(mockProcessManager.run(getConstFinderArgs(appDill.path))).called(1);
+    verifyNever(mockProcessManager.start(fontSubsetArgs));
+  });
+
+  testWithoutContext('font-subset throws on write to sdtin', () async {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+    final File appDill = environment.buildDir.childFile('app.dill')..createSync(recursive: true);
+    fs.file(inputPath).createSync(recursive: true);
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    final mocks.CompleterIOSink stdinSink = mocks.CompleterIOSink(throwOnAdd: true);
+    _addConstFinderInvocation(appDill.path, stdout: validConstFinderResult);
+    _resetFontSubsetInvocation(exitCode: -1, stdinSink: stdinSink);
+
+    expect(
+      iconTreeShaker.subsetFont(
+        inputPath: inputPath,
+        outputPath: outputPath,
+        relativePath: relativePath,
+      ),
+      throwsA(isA<IconTreeShakerException>()),
+    );
+
+    verify(mockProcessManager.run(getConstFinderArgs(appDill.path))).called(1);
+    verifyNever(mockProcessManager.start(fontSubsetArgs));
+  });
+
+  testWithoutContext('Invalid font manifest', () async {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+    final File appDill = environment.buildDir.childFile('app.dill')..createSync(recursive: true);
+    fs.file(inputPath).createSync(recursive: true);
+
+    fontManifestContent = DevFSStringContent(invalidFontManifestJson);
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    _addConstFinderInvocation(appDill.path, stdout: validConstFinderResult);
+
+    expect(
+      iconTreeShaker.subsetFont(
+        inputPath: inputPath,
+        outputPath: outputPath,
+        relativePath: relativePath,
+      ),
+      throwsA(isA<IconTreeShakerException>()),
+    );
+
+    verify(mockProcessManager.run(getConstFinderArgs(appDill.path))).called(1);
+    verifyNever(mockProcessManager.start(fontSubsetArgs));
+  });
+
+  testWithoutContext('ConstFinder non-zero exit', () async {
+    final Environment environment = _createEnvironment(<String, String>{
+      kIconTreeShakerFlag: 'true',
+      kBuildMode: 'release',
+    });
+    final File appDill = environment.buildDir.childFile('app.dill')..createSync(recursive: true);
+    fs.file(inputPath).createSync(recursive: true);
+
+    fontManifestContent = DevFSStringContent(invalidFontManifestJson);
+
+    final IconTreeShaker iconTreeShaker = IconTreeShaker(
+      environment,
+      fontManifestContent,
+      logger: logger,
+      processManager: mockProcessManager,
+      fileSystem: fs,
+      artifacts: mockArtifacts,
+    );
+
+    _addConstFinderInvocation(appDill.path, exitCode: -1);
+
+    expect(
+      iconTreeShaker.subsetFont(
+        inputPath: inputPath,
+        outputPath: outputPath,
+        relativePath: relativePath,
+      ),
+      throwsA(isA<IconTreeShakerException>()),
+    );
+
+    verify(mockProcessManager.run(getConstFinderArgs(appDill.path))).called(1);
+    verifyNever(mockProcessManager.start(fontSubsetArgs));
+  });
+}
+
+const String validConstFinderResult = '''
+{
+  "constantInstances": [
+    {
+      "codePoint": 59470,
+      "fontFamily": "MaterialIcons",
+      "fontPackage": null,
+      "matchTextDirection": false
+    }
+  ],
+  "nonConstantLocations": []
+}
+''';
+
+const String constFinderResultWithInvalid = '''
+{
+  "constantInstances": [
+    {
+      "codePoint": 59470,
+      "fontFamily": "MaterialIcons",
+      "fontPackage": null,
+      "matchTextDirection": false
+    }
+  ],
+  "nonConstantLocations": [
+    {
+      "file": "file:///Path/to/hello_world/lib/file.dart",
+      "line": 19,
+      "column": 11
+    }
+  ]
+}
+''';
+
+const String validFontManifestJson = '''
+[
+  {
+    "family": "MaterialIcons",
+    "fonts": [
+      {
+        "asset": "fonts/MaterialIcons-Regular.ttf"
+      }
+    ]
+  },
+  {
+    "family": "GalleryIcons",
+    "fonts": [
+      {
+        "asset": "packages/flutter_gallery_assets/fonts/private/gallery_icons/GalleryIcons.ttf"
+      }
+    ]
+  },
+  {
+    "family": "packages/cupertino_icons/CupertinoIcons",
+    "fonts": [
+      {
+        "asset": "packages/cupertino_icons/assets/CupertinoIcons.ttf"
+      }
+    ]
+  }
+]
+''';
+
+const String invalidFontManifestJson = '''
+{
+  "famly": "MaterialIcons",
+  "fonts": [
+    {
+      "asset": "fonts/MaterialIcons-Regular.ttf"
+    }
+  ]
+}
+''';
+
+class MockProcessManager extends Mock implements ProcessManager {}
+class MockProcess extends Mock implements Process {}
+class MockArtifacts extends Mock implements Artifacts {}

packages/flutter_tools/test/general.shard/bundle_shim_test.dart

@@ -39,6 +39,7 @@ void main() {
       targetPlatform: TargetPlatform.ios,
       depfilePath: 'example.d',
       precompiled: false,
+      treeShakeIcons: false,
     );
     expect(globals.fs.file(globals.fs.path.join('example', 'kernel_blob.bin')).existsSync(), true);
     expect(globals.fs.file(globals.fs.path.join('example', 'LICENSE')).existsSync(), true);
@@ -61,6 +62,7 @@ void main() {
       targetPlatform: TargetPlatform.linux_x64,
       depfilePath: 'example.d',
       precompiled: false,
+      treeShakeIcons: false,
     ), throwsToolExit());
   }));
 }

packages/flutter_tools/test/general.shard/fuchsia/fuchsia_device_test.dart

@@ -720,7 +720,7 @@ void main() {
         app = BuildableFuchsiaApp(project: FlutterProject.current().fuchsia);
       }
 
-      final DebuggingOptions debuggingOptions = DebuggingOptions.disabled(BuildInfo(mode, null));
+      final DebuggingOptions debuggingOptions = DebuggingOptions.disabled(BuildInfo(mode, null, treeShakeIcons: false));
       return await device.startApp(
         app,
         prebuiltApplication: prebuilt,
@@ -753,7 +753,7 @@ void main() {
 
       final FuchsiaApp app = FuchsiaApp.fromPrebuiltApp(far);
       final DebuggingOptions debuggingOptions =
-          DebuggingOptions.disabled(const BuildInfo(BuildMode.release, null));
+          DebuggingOptions.disabled(const BuildInfo(BuildMode.release, null, treeShakeIcons: false));
       final LaunchResult launchResult = await device.startApp(app,
           prebuiltApplication: true,
           debuggingOptions: debuggingOptions);

packages/flutter_tools/test/general.shard/ios/devices_test.dart

@@ -292,7 +292,7 @@ void main() {
 
         final LaunchResult launchResult = await device.startApp(mockApp,
           prebuiltApplication: true,
-          debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null)),
+          debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null, treeShakeIcons: false)),
           platformArgs: <String, dynamic>{},
         );
         verify(mockUsage.sendEvent('ios-mdns', 'success')).called(1);
@@ -362,7 +362,7 @@ void main() {
 
         final LaunchResult launchResult = await device.startApp(mockApp,
           prebuiltApplication: true,
-          debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null)),
+          debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null, treeShakeIcons: false)),
           platformArgs: <String, dynamic>{},
         );
         verify(mockUsage.sendEvent('ios-mdns', 'failure')).called(1);
@@ -395,7 +395,7 @@ void main() {
 
         final LaunchResult launchResult = await device.startApp(mockApp,
             prebuiltApplication: true,
-            debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null)),
+            debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null, treeShakeIcons: false)),
             platformArgs: <String, dynamic>{},
         );
         verify(mockUsage.sendEvent('ios-mdns', 'failure')).called(1);
@@ -416,7 +416,7 @@ void main() {
         final IOSDevice device = IOSDevice('123');
         final LaunchResult launchResult = await device.startApp(mockApp,
           prebuiltApplication: true,
-          debuggingOptions: DebuggingOptions.disabled(const BuildInfo(BuildMode.release, null)),
+          debuggingOptions: DebuggingOptions.disabled(const BuildInfo(BuildMode.release, null, treeShakeIcons: false)),
           platformArgs: <String, dynamic>{},
         );
         expect(launchResult.started, isTrue);
@@ -455,7 +455,7 @@ void main() {
         final LaunchResult launchResult = await device.startApp(mockApp,
           prebuiltApplication: true,
           debuggingOptions: DebuggingOptions.enabled(
-              const BuildInfo(BuildMode.debug, null),
+              const BuildInfo(BuildMode.debug, null, treeShakeIcons: false),
               cacheSkSL: true,
           ),
           platformArgs: <String, dynamic>{},
@@ -499,7 +499,7 @@ void main() {
         final LaunchResult launchResult = await device.startApp(mockApp,
           prebuiltApplication: true,
           debuggingOptions: DebuggingOptions.enabled(
-            const BuildInfo(BuildMode.debug, null),
+            const BuildInfo(BuildMode.debug, null, treeShakeIcons: false),
             deviceVmServicePort: 8181,
           ),
           platformArgs: <String, dynamic>{},
@@ -600,7 +600,7 @@ void main() {
             device.startApp(
               app,
               prebuiltApplication: false,
-              debuggingOptions: DebuggingOptions.disabled(const BuildInfo(BuildMode.debug, null)),
+              debuggingOptions: DebuggingOptions.disabled(const BuildInfo(BuildMode.debug, null, treeShakeIcons: false)),
               platformArgs: <String, dynamic>{},
             ).then((LaunchResult result) {
               completer.complete(result);

packages/flutter_tools/test/general.shard/ios/simulators_test.dart

@@ -10,6 +10,7 @@ import 'package:flutter_tools/src/build_info.dart';
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/targets/dart.dart';
+import 'package:flutter_tools/src/build_system/targets/icon_tree_shaker.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/application_package.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
@@ -219,6 +220,7 @@ void main() {
       kTargetPlatform: 'ios',
       kBuildMode: 'debug',
       kTrackWidgetCreation: 'false',
+      kIconTreeShakerFlag: null,
     });
   }, overrides: <Type, Generator>{
     BuildSystem: () => MockBuildSystem(),
@@ -501,7 +503,7 @@ void main() {
       final Directory mockDir = globals.fs.currentDirectory;
       final IOSApp package = PrebuiltIOSApp(projectBundleId: 'incorrect', bundleName: 'name', bundleDir: mockDir);
 
-      const BuildInfo mockInfo = BuildInfo(BuildMode.debug, 'flavor');
+      const BuildInfo mockInfo = BuildInfo(BuildMode.debug, 'flavor', treeShakeIcons: false);
       final DebuggingOptions mockOptions = DebuggingOptions.disabled(mockInfo);
       await device.startApp(package, prebuiltApplication: true, debuggingOptions: mockOptions);
 

packages/flutter_tools/test/general.shard/ios/xcodeproj_test.dart

@@ -350,14 +350,14 @@ Information about project "Runner":
   });
 
   testWithoutContext('expected scheme for flavored build is the title-cased flavor', () {
-    expect(XcodeProjectInfo.expectedSchemeFor(const BuildInfo(BuildMode.debug, 'hello')), 'Hello');
-    expect(XcodeProjectInfo.expectedSchemeFor(const BuildInfo(BuildMode.profile, 'HELLO')), 'HELLO');
-    expect(XcodeProjectInfo.expectedSchemeFor(const BuildInfo(BuildMode.release, 'Hello')), 'Hello');
+    expect(XcodeProjectInfo.expectedSchemeFor(const BuildInfo(BuildMode.debug, 'hello', treeShakeIcons: false)), 'Hello');
+    expect(XcodeProjectInfo.expectedSchemeFor(const BuildInfo(BuildMode.profile, 'HELLO', treeShakeIcons: false)), 'HELLO');
+    expect(XcodeProjectInfo.expectedSchemeFor(const BuildInfo(BuildMode.release, 'Hello', treeShakeIcons: false)), 'Hello');
   });
   testWithoutContext('expected build configuration for flavored build is Mode-Flavor', () {
-    expect(XcodeProjectInfo.expectedBuildConfigurationFor(const BuildInfo(BuildMode.debug, 'hello'), 'Hello'), 'Debug-Hello');
-    expect(XcodeProjectInfo.expectedBuildConfigurationFor(const BuildInfo(BuildMode.profile, 'HELLO'), 'Hello'), 'Profile-Hello');
-    expect(XcodeProjectInfo.expectedBuildConfigurationFor(const BuildInfo(BuildMode.release, 'Hello'), 'Hello'), 'Release-Hello');
+    expect(XcodeProjectInfo.expectedBuildConfigurationFor(const BuildInfo(BuildMode.debug, 'hello', treeShakeIcons: false), 'Hello'), 'Debug-Hello');
+    expect(XcodeProjectInfo.expectedBuildConfigurationFor(const BuildInfo(BuildMode.profile, 'HELLO', treeShakeIcons: false), 'Hello'), 'Profile-Hello');
+    expect(XcodeProjectInfo.expectedBuildConfigurationFor(const BuildInfo(BuildMode.release, 'Hello', treeShakeIcons: false), 'Hello'), 'Release-Hello');
   });
 
   testWithoutContext('scheme for default project is Runner', () {
@@ -366,7 +366,7 @@ Information about project "Runner":
     expect(info.schemeFor(BuildInfo.debug), 'Runner');
     expect(info.schemeFor(BuildInfo.profile), 'Runner');
     expect(info.schemeFor(BuildInfo.release), 'Runner');
-    expect(info.schemeFor(const BuildInfo(BuildMode.debug, 'unknown')), isNull);
+    expect(info.schemeFor(const BuildInfo(BuildMode.debug, 'unknown', treeShakeIcons: false)), isNull);
   });
 
   testWithoutContext('build configuration for default project is matched against BuildMode', () {
@@ -384,11 +384,11 @@ Information about project "Runner":
       <String>['Free', 'Paid'],
     );
 
-    expect(info.schemeFor(const BuildInfo(BuildMode.debug, 'free')), 'Free');
-    expect(info.schemeFor(const BuildInfo(BuildMode.profile, 'Free')), 'Free');
-    expect(info.schemeFor(const BuildInfo(BuildMode.release, 'paid')), 'Paid');
-    expect(info.schemeFor(const BuildInfo(BuildMode.debug, null)), isNull);
-    expect(info.schemeFor(const BuildInfo(BuildMode.debug, 'unknown')), isNull);
+    expect(info.schemeFor(const BuildInfo(BuildMode.debug, 'free', treeShakeIcons: false)), 'Free');
+    expect(info.schemeFor(const BuildInfo(BuildMode.profile, 'Free', treeShakeIcons: false)), 'Free');
+    expect(info.schemeFor(const BuildInfo(BuildMode.release, 'paid', treeShakeIcons: false)), 'Paid');
+    expect(info.schemeFor(const BuildInfo(BuildMode.debug, null, treeShakeIcons: false)), isNull);
+    expect(info.schemeFor(const BuildInfo(BuildMode.debug, 'unknown', treeShakeIcons: false)), isNull);
   });
 
   testWithoutContext('build configuration for project with custom schemes is matched against BuildMode and flavor', () {
@@ -398,10 +398,10 @@ Information about project "Runner":
       <String>['Free', 'Paid'],
     );
 
-    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.debug, 'free'), 'Free'), 'debug (free)');
-    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.debug, 'Paid'), 'Paid'), 'Debug paid');
-    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.profile, 'FREE'), 'Free'), 'profile - Free');
-    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.release, 'paid'), 'Paid'), 'Release-Paid');
+    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.debug, 'free', treeShakeIcons: false), 'Free'), 'debug (free)');
+    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.debug, 'Paid', treeShakeIcons: false), 'Paid'), 'Debug paid');
+    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.profile, 'FREE', treeShakeIcons: false), 'Free'), 'profile - Free');
+    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.release, 'paid', treeShakeIcons: false), 'Paid'), 'Release-Paid');
   });
 
   testWithoutContext('build configuration for project with inconsistent naming is null', () {
@@ -410,9 +410,9 @@ Information about project "Runner":
       <String>['Debug-F', 'Dbg Paid', 'Rel Free', 'Release Full'],
       <String>['Free', 'Paid'],
     );
-    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.debug, 'Free'), 'Free'), null);
-    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.profile, 'Free'), 'Free'), null);
-    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.release, 'Paid'), 'Paid'), null);
+    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.debug, 'Free', treeShakeIcons: false), 'Free'), null);
+    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.profile, 'Free', treeShakeIcons: false), 'Free'), null);
+    expect(info.buildConfigurationFor(const BuildInfo(BuildMode.release, 'Paid', treeShakeIcons: false), 'Paid'), null);
   });
  group('environmentVariablesAsXcodeBuildSettings', () {
     FakePlatform platform;
@@ -461,7 +461,7 @@ Information about project "Runner":
           platform: TargetPlatform.ios, mode: anyNamed('mode'))).thenReturn('engine');
       when(mockArtifacts.engineOutPath).thenReturn(fs.path.join('out', 'ios_profile_arm'));
 
-      const BuildInfo buildInfo = BuildInfo(BuildMode.debug, null);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.debug, null, treeShakeIcons: false);
       final FlutterProject project = FlutterProject.fromPath('path/to/project');
       await updateGeneratedXcodeProperties(
         project: project,
@@ -485,7 +485,7 @@ Information about project "Runner":
       when(mockArtifacts.getArtifactPath(Artifact.flutterFramework,
           platform: TargetPlatform.ios, mode: anyNamed('mode'))).thenReturn('engine');
       when(mockArtifacts.engineOutPath).thenReturn(fs.path.join('out', 'ios_profile_arm'));
-      const BuildInfo buildInfo = BuildInfo(BuildMode.debug, null, trackWidgetCreation: true);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.debug, null, trackWidgetCreation: true, treeShakeIcons: false);
       final FlutterProject project = FlutterProject.fromPath('path/to/project');
       await updateGeneratedXcodeProperties(
         project: project,
@@ -509,7 +509,7 @@ Information about project "Runner":
       when(mockArtifacts.getArtifactPath(Artifact.flutterFramework,
           platform: TargetPlatform.ios, mode: anyNamed('mode'))).thenReturn('engine');
       when(mockArtifacts.engineOutPath).thenReturn(fs.path.join('out', 'ios_profile_arm'));
-      const BuildInfo buildInfo = BuildInfo(BuildMode.debug, null);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.debug, null, treeShakeIcons: false);
       final FlutterProject project = FlutterProject.fromPath('path/to/project');
       await updateGeneratedXcodeProperties(
         project: project,
@@ -533,7 +533,7 @@ Information about project "Runner":
       when(mockArtifacts.getArtifactPath(Artifact.flutterFramework,
           platform: TargetPlatform.ios, mode: anyNamed('mode'))).thenReturn('engine');
       when(mockArtifacts.engineOutPath).thenReturn(fs.path.join('out', 'ios_profile'));
-      const BuildInfo buildInfo = BuildInfo(BuildMode.debug, null);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.debug, null, treeShakeIcons: false);
 
       final FlutterProject project = FlutterProject.fromPath('path/to/project');
       await updateGeneratedXcodeProperties(
@@ -595,7 +595,7 @@ dependencies:
 flutter:
 ''';
 
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,
@@ -613,7 +613,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,
@@ -631,7 +631,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,
@@ -649,7 +649,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,
@@ -667,7 +667,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildNumber: '3');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildNumber: '3', treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,
@@ -685,7 +685,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3', treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,
@@ -703,7 +703,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3', treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,
@@ -720,7 +720,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3');
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, buildName: '1.0.2', buildNumber: '3', treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,
@@ -737,7 +737,7 @@ dependencies:
     sdk: flutter
 flutter:
 ''';
-      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null);
+      const BuildInfo buildInfo = BuildInfo(BuildMode.release, null, treeShakeIcons: false);
       await checkBuildVersion(
         manifestString: manifest,
         buildInfo: buildInfo,

packages/flutter_tools/test/general.shard/tester/flutter_tester_test.dart

@@ -148,7 +148,7 @@ void main() {
       testUsingContext('not debug', () async {
         final LaunchResult result = await device.startApp(null,
             mainPath: mainPath,
-            debuggingOptions: DebuggingOptions.disabled(const BuildInfo(BuildMode.release, null)));
+            debuggingOptions: DebuggingOptions.disabled(const BuildInfo(BuildMode.release, null, treeShakeIcons: false)));
 
         expect(result.started, isFalse);
       }, overrides: startOverrides);
@@ -166,7 +166,7 @@ Hello!
 
         final LaunchResult result = await device.startApp(null,
             mainPath: mainPath,
-            debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null)));
+            debuggingOptions: DebuggingOptions.enabled(const BuildInfo(BuildMode.debug, null, treeShakeIcons: false)));
         expect(result.started, isTrue);
         expect(result.observatoryUri, observatoryUri);
         expect(logLines.last, 'Hello!');

packages/flutter_tools/test/src/mocks.dart

@@ -372,7 +372,7 @@ class CompleterIOSink extends MemoryIOSink {
       _completer.complete(throwOnAdd ? <int>[] : data);
     }
     if (throwOnAdd) {
-      throw 'CompleterIOSink Error';
+      throw Exception('CompleterIOSink Error');
     }
     super.add(data);
   }