restore arrow function bind this workaround

lib/src/options.dart

 // Copyright (c) 2014, 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.
 
 /// Set of flags and options passed to the compiler
 library dev_compiler.src.options;
 
 import 'dart:io';
 
 import 'package:args/args.dart';
@@ skipping 42 matching lines @@
 class CodegenOptions {
   /// Whether to emit the source map files.
   final bool emitSourceMaps;
 
   /// Whether to force compilation of code with static errors.
   final bool forceCompile;
 
   /// Output directory for generated code.
   final String outputDir;
 
-  const CodegenOptions(
-      {this.emitSourceMaps: true, this.forceCompile: false, this.outputDir});
+  /// Whether to emit a workaround for missing arrow function bind-this in
+  /// other V8 builds
+  final bool arrowFnBindThisWorkaround;
+
+  const CodegenOptions({this.emitSourceMaps: true, this.forceCompile: false,
+      this.outputDir, this.arrowFnBindThisWorkaround: false});
 }
 
 /// General options used by the dev compiler and server.
 class CompilerOptions {
   final StrongModeOptions strongOptions;
   final SourceResolverOptions sourceOptions;
   final CodegenOptions codegenOptions;
 
   /// Whether to check the sdk libraries.
   final bool checkSdk;
@@ skipping 93 matching lines @@
     }
     customUrlMappings[splitMapping[0]] = splitMapping[1];
   }
 
   if (serverMode && args.rest.length != 1) showUsage = true;
 
   return new CompilerOptions(
       codegenOptions: new CodegenOptions(
           emitSourceMaps: args['source-maps'],
           forceCompile: args['force-compile'] || serverMode,
-          outputDir: outputDir),
+          outputDir: outputDir,
+          arrowFnBindThisWorkaround: args['arrow-fn-bind-this']),
       sourceOptions: new SourceResolverOptions(
           useMockSdk: args['mock-sdk'],
           dartSdkPath: sdkPath,
           useImplicitHtml: serverMode &&
               args.rest.length == 1 &&
               args.rest[0].endsWith('.dart'),
           customUrlMappings: customUrlMappings,
           useMultiPackage: args['use-multi-package'],
           packageRoot: args['package-root'],
           packagePaths: args['package-paths'].split(','),
@@ skipping 41 matching lines @@
       defaultsTo: false)
   ..addOption('package-paths',
       help: 'if using the multi-package resolver, the list of directories to\n'
       'look for packages in.', defaultsTo: '')
   ..addOption('resources',
       help: 'Additional resources to serve', defaultsTo: '')
   ..addFlag('source-maps',
       help: 'Whether to emit source map files', defaultsTo: true)
   ..addOption('runtime-dir',
       help: 'Where to find dev_compiler\'s runtime files', defaultsTo: null)
+  ..addFlag('arrow-fn-bind-this',
+      help: 'Work around `this` binding in => functions')
 
   // general options
   ..addFlag('help', abbr: 'h', help: 'Display this message')
   ..addFlag('server', help: 'Run as a development server.', defaultsTo: false)
   ..addFlag('hashing',
       help: 'Enable hash-based file caching.', defaultsTo: null)
   ..addFlag('widget',
       help: 'Serve embedded widget with static errors and warnings.',
       defaultsTo: true)
   ..addOption('host',
@@ skipping 56 matching lines @@
     // The pub-cache directory is two levels up, but we verify that the layout
     // looks correct.
     if (path.basename(dir) != 'dev_compiler') return null;
     dir = path.dirname(dir);
     if (path.basename(dir) != 'global_packages') return null;
     dir = path.dirname(dir);
     return path.join(dir, cacheDir, 'lib', 'runtime');
   }
   return null;
 }