Disable closure wrapping by default

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 61 matching lines @@
   static const inferDownwardsDefault = true;
 
   /// Whether to inject casts between Dart assignable types.
   final bool relaxedCasts;
 
   /// Whether to use static types for code generation.
   final bool ignoreTypes;
 
   /// Whether to wrap closures for compatibility.
   final bool wrapClosures;
-  static const wrapClosuresDefault = true;
+  static const wrapClosuresDefault = false;
 
   RulesOptions({this.allowConstCasts: true, this.covariantGenerics: true,
       this.inferDownwards: inferDownwardsDefault, this.relaxedCasts: true,
       this.ignoreTypes: false, this.wrapClosures: wrapClosuresDefault});
 }
 
 class JSCodeOptions {
   /// Whether to emit the source map files.
   final bool emitSourceMaps;
 
@@ skipping 327 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;
 }