- Remove passing of obsolete parameter in dart2js.

utils/compiler/build_helper.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.
 
 #import('dart:io');
 #import('dart:uri');
 
 #import('../../lib/compiler/implementation/util/uri_extras.dart');
 #import('../../lib/compiler/implementation/filenames.dart');
 
@@ skipping 55 matching lines @@
   Uri dart2jsUri = dartUri.resolve('lib/compiler/implementation/dart2js.dart');
   String dart2jsPath = relativize(dartVmLocation, dart2jsUri);
   String dart2jsPathWin = dart2jsPath.replaceAll("/", "\\");
 
   print('dartUri = $dartUri');
   print('dartVmLocation = $dartVmLocation');
   print('dart2jsUri = $dart2jsUri');
   print('dart2jsPath = $dart2jsPath');
   print('dart2jsPathWin = $dart2jsPathWin');
 
-  // Disable String operator+. This should only be necessary
-  // temporarily as the operator will go away soon.
-  // TODO(ahe): Remove this option.
-  options = ' --allow_string_plus=false$options';
+  options = ' $options';
 
   // Tell the VM to grow the heap more aggressively. This should only
   // be necessary temporarily until the VM is better at detecting how
   // applications use memory.
   // TODO(ahe): Remove this option.
   options = ' --heap_growth_rate=32$options';
 
   return [
 '''
 #!/bin/sh
@@ skipping 13 matching lines @@
 set SCRIPTPATH=%~dp0
 
 REM Does the path have a trailing slash? If so, remove it.
 if %SCRIPTPATH:~-1%==\ set SCRIPTPATH=%SCRIPTPATH:~0,-1%
 
 set arguments=%*
 
 "%SCRIPTPATH%\dart.exe"$options "%SCRIPTPATH%$dart2jsPathWin" %arguments%
 '''.replaceAll('\n', '\r\n')];
 }