Address early review comments

build_web_compilers/lib/src/dart2wasm_bootstrap.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
+// for details. 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:convert';
 import 'dart:io';
 
@@ -65,6 +69,8 @@ https://github.com/dart-lang/build/blob/master/docs/faq.md#how-can-i-resolve-ski
 
  args = [
  '--packages=$multiRootScheme:///.dart_tool/package_config.json',
+ // The -E prefix is removed by dartdev when starting the actual dart2wasm
+ // process.
  '-E--multi-root-scheme=$multiRootScheme',
  '-E--multi-root=${scratchSpace.tempDir.uri.toFilePath()}',
  for (var experiment in enabledExperiments)

build_web_compilers/lib/src/platforms.dart

@@ -5,7 +5,7 @@
 import 'package:build_modules/build_modules.dart';
 
 /// `dart:` SDK libraries available in every platform supported by
-/// build_webc_compilers.
+/// build_web_compilers.
 const _coreLibraries = [
  '_internal',
  'async',
@@ -39,11 +39,11 @@ const _additionalWasmLibraries = [
  'ffi',
 ];
 
-const _libraries = [..._coreLibraries, ..._additionalWebLibraries];
+const _jsCompilerLibraries = [..._coreLibraries, ..._additionalWebLibraries];
 
-final ddcPlatform = DartPlatform.register('ddc', _libraries);
+final ddcPlatform = DartPlatform.register('ddc', _jsCompilerLibraries);
 
-final dart2jsPlatform = DartPlatform.register('dart2js', _libraries);
+final dart2jsPlatform = DartPlatform.register('dart2js', _jsCompilerLibraries);
 
 final dart2wasmPlatform = DartPlatform.register(
  'dart2wasm', [..._coreLibraries, ..._additionalWasmLibraries]);