[flutter_tools] Add --dump-info, --no-frequency-based-minification flags (#115862)

* [flutter_tools] Add --dump-info, --no-frequency-based-minification flags

Also some cleanup to named arguments to the buildWeb function

Fixes https://github.com/flutter/flutter/issues/115854

* fix tests

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

@@ -36,6 +36,12 @@ const String kHasWebPlugins = 'HasWebPlugins';
 /// Valid values are O1 (lowest, profile default) to O4 (highest, release default).
 const String kDart2jsOptimization = 'Dart2jsOptimization';
 
+/// If `--dump-info` should be passed to dart2js.
+const String kDart2jsDumpInfo = 'Dart2jsDumpInfo';
+
+// If `--no-frequency-based-minification` should be based to dart2js
+const String kDart2jsNoFrequencyBasedMinification = 'Dart2jsNoFrequencyBasedMinification';
+
 /// Whether to disable dynamic generation code to satisfy csp policies.
 const String kCspMode = 'cspMode';
 
@@ -217,6 +223,8 @@ class Dart2JSTarget extends Target {
     }
 
     final String? dart2jsOptimization = environment.defines[kDart2jsOptimization];
+    final bool dumpInfo = environment.defines[kDart2jsDumpInfo] == 'true';
+    final bool noFrequencyBasedMinification = environment.defines[kDart2jsNoFrequencyBasedMinification] == 'true';
     final File outputJSFile = environment.buildDir.childFile('main.dart.js');
     final bool csp = environment.defines[kCspMode] == 'true';
 
@@ -224,6 +232,8 @@ class Dart2JSTarget extends Target {
       ...sharedCommandOptions,
       if (dart2jsOptimization != null) '-$dart2jsOptimization' else '-O4',
       if (buildMode == BuildMode.profile) '--no-minify',
+      if (dumpInfo) '--dump-info',
+      if (noFrequencyBasedMinification) '--no-frequency-based-minification',
       if (csp) '--csp',
       '-o',
       outputJSFile.path,

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

@@ -70,6 +70,14 @@ class BuildWebCommand extends BuildSubCommand {
       help: 'Sets the optimization level used for Dart compilation to JavaScript. '
           'Valid values range from O0 to O4.'
     );
+    argParser.addFlag('dump-info', negatable: false,
+      help: 'Passes "--dump-info" to the Javascript compiler which generates '
+          'information about the generated code is a .js.info.json file.'
+    );
+    argParser.addFlag('no-frequency-based-minification', negatable: false,
+      help: 'Disables the frequency based minifier. '
+          'Useful for comparing the output between builds.'
+    );
   }
 
   final FileSystem _fileSystem;
@@ -132,9 +140,11 @@ class BuildWebCommand extends BuildSubCommand {
       stringArgDeprecated('pwa-strategy')!,
       boolArgDeprecated('source-maps'),
       boolArgDeprecated('native-null-assertions'),
-      baseHref,
-      stringArgDeprecated('dart2js-optimization'),
+      baseHref: baseHref,
+      dart2jsOptimization: stringArgDeprecated('dart2js-optimization'),
       outputDirectoryPath: outputDirectoryPath,
+      dumpInfo: boolArgDeprecated('dump-info'),
+      noFrequencyBasedMinification: boolArgDeprecated('no-frequency-based-minification'),
     );
     return FlutterCommandResult.success();
   }

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

@@ -298,8 +298,6 @@ class ResidentWebRunner extends ResidentRunner {
             kNoneWorker,
             true,
             debuggingOptions.nativeNullAssertions,
-            null,
-            null,
           );
         }
         await device!.device!.startApp(
@@ -372,8 +370,7 @@ class ResidentWebRunner extends ResidentRunner {
           kNoneWorker,
           true,
           debuggingOptions.nativeNullAssertions,
-          kBaseHref,
-          null,
+          baseHref: kBaseHref,
         );
       } on ToolExit {
         return OperationResult(1, 'Failed to recompile application.');

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

@@ -25,11 +25,13 @@ Future<void> buildWeb(
   bool csp,
   String serviceWorkerStrategy,
   bool sourceMaps,
-  bool nativeNullAssertions,
-  String? baseHref,
+  bool nativeNullAssertions, {
   String? dart2jsOptimization,
-  {String? outputDirectoryPath}
-) async {
+  String? baseHref,
+  bool dumpInfo = false,
+  bool noFrequencyBasedMinification = false,
+  String? outputDirectoryPath,
+}) async {
   final bool hasWebPlugins = (await findPlugins(flutterProject))
     .any((Plugin p) => p.platforms.containsKey(WebPlugin.kConfigKey));
   final Directory outputDirectory = outputDirectoryPath == null
@@ -66,6 +68,8 @@ Future<void> buildWeb(
          kServiceWorkerStrategy: serviceWorkerStrategy,
         if (dart2jsOptimization != null)
          kDart2jsOptimization: dart2jsOptimization,
+        kDart2jsDumpInfo: dumpInfo.toString(),
+        kDart2jsNoFrequencyBasedMinification: noFrequencyBasedMinification.toString(),
         ...buildInfo.toBuildSystemEnvironment(),
       },
       artifacts: globals.artifacts!,

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

@@ -130,6 +130,8 @@ void main() {
         'SourceMaps': 'false',
         'NativeNullAssertions': 'true',
         'ServiceWorkerStrategy': 'offline-first',
+        'Dart2jsDumpInfo': 'false',
+        'Dart2jsNoFrequencyBasedMinification': 'false',
         'Dart2jsOptimization': 'O3',
         'BuildMode': 'release',
         'DartDefines': 'Zm9vPWE=,RkxVVFRFUl9XRUJfQVVUT19ERVRFQ1Q9dHJ1ZQ==',
@@ -179,6 +181,8 @@ void main() {
         'SourceMaps': 'false',
         'NativeNullAssertions': 'true',
         'ServiceWorkerStrategy': 'offline-first',
+        'Dart2jsDumpInfo': 'false',
+        'Dart2jsNoFrequencyBasedMinification': 'false',
         'BuildMode': 'release',
         'DartDefines': 'RkxVVFRFUl9XRUJfQVVUT19ERVRFQ1Q9dHJ1ZQ==',
         'DartObfuscation': 'false',

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

@@ -659,6 +659,74 @@ void main() {
     ProcessManager: () => processManager,
   }));
 
+  test('Dart2JSTarget calls dart2js with expected args with dump-info', () => testbed.run(() async {
+    environment.defines[kBuildMode] = 'profile';
+    environment.defines[kDart2jsDumpInfo] = 'true';
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ...kDart2jsLinuxArgs,
+        '-Ddart.vm.profile=true',
+        '--no-source-maps',
+        '-o',
+        environment.buildDir.childFile('app.dill').absolute.path,
+        '--packages=.dart_tool/package_config.json',
+        '--cfe-only',
+        environment.buildDir.childFile('main.dart').absolute.path,
+      ]
+    ));
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ...kDart2jsLinuxArgs,
+        '-Ddart.vm.profile=true',
+        '--no-source-maps',
+        '-O4',
+        '--no-minify',
+        '--dump-info',
+        '-o',
+        environment.buildDir.childFile('main.dart.js').absolute.path,
+        environment.buildDir.childFile('app.dill').absolute.path,
+      ]
+    ));
+
+    await const Dart2JSTarget().build(environment);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => processManager,
+  }));
+
+  test('Dart2JSTarget calls dart2js with expected args with no-frequency-based-minification', () => testbed.run(() async {
+    environment.defines[kBuildMode] = 'profile';
+    environment.defines[kDart2jsNoFrequencyBasedMinification] = 'true';
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ...kDart2jsLinuxArgs,
+        '-Ddart.vm.profile=true',
+        '--no-source-maps',
+        '-o',
+        environment.buildDir.childFile('app.dill').absolute.path,
+        '--packages=.dart_tool/package_config.json',
+        '--cfe-only',
+        environment.buildDir.childFile('main.dart').absolute.path,
+      ]
+    ));
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ...kDart2jsLinuxArgs,
+        '-Ddart.vm.profile=true',
+        '--no-source-maps',
+        '-O4',
+        '--no-minify',
+        '--no-frequency-based-minification',
+        '-o',
+        environment.buildDir.childFile('main.dart.js').absolute.path,
+        environment.buildDir.childFile('app.dill').absolute.path,
+      ]
+    ));
+
+    await const Dart2JSTarget().build(environment);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => processManager,
+  }));
+
   test('Generated service worker is empty with none-strategy', () {
     final String result = generateServiceWorker(<String, String>{'/foo': 'abcd'}, <String>[], serviceWorkerStrategy: ServiceWorkerStrategy.none);