fixes #43, remove => workaround

lib/src/js/printer.dart

 // Copyright (c) 2012, 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.
 
 part of js_ast;
 
 
 class JavaScriptPrintingOptions {
   final bool shouldCompressOutput;
   final bool minifyLocalVariables;
@@ skipping 826 matching lines @@
 
   visitNamedFunction(NamedFunction namedFunction) {
     functionOut(namedFunction.function, namedFunction.name);
   }
 
   visitFun(Fun fun) {
     functionOut(fun, null);
   }
 
   visitArrowFun(ArrowFun fun) {
-    if (fun.bindThisWorkaround) {
-      out("(");
-    }
     localNamer.enterScope(fun);
     if (fun.params.length == 1) {
       visitNestedExpression(fun.params.single, PRIMARY,
           newInForInit: false, newAtStatementBegin: false);
     } else {
       out("(");
       visitCommaSeparated(fun.params, PRIMARY,
           newInForInit: false, newAtStatementBegin: false);
       out(")");
     }
     spaceOut();
     out("=>");
     if (fun.body is Expression) {
       spaceOut();
       // Object initializers require parenthesis to disambiguate
       // AssignmentExpression from FunctionBody. See:
       // https://people.mozilla.org/~jorendorff/es6-draft.html#sec-arrow-function-definitions
       var needsParen = fun.body is ObjectInitializer;
       if (needsParen) out("(");
       visitNestedExpression(fun.body, ASSIGNMENT,
           newInForInit: false, newAtStatementBegin: false);
       if (needsParen) out(")");
     } else {
       blockBody(fun.body, needsSeparation: false, needsNewline: false);
     }
     localNamer.leaveScope();
-    if (fun.bindThisWorkaround) {
-      out(").bind(this)");
-    }
   }
 
   visitLiteralBool(LiteralBool node) {
     out(node.value ? "true" : "false");
   }
 
   visitLiteralString(LiteralString node) {
     out(node.value);
   }
 
@@ skipping 548 matching lines @@
     declare(node.name);
     node.function.accept(this);
   }
 
   visitClassExpression(ClassExpression node) {
     declare(node.name);
     if (node.heritage != null) node.heritage.accept(this);
     for (Method element in node.methods) element.accept(this);
   }
 }