Add dart2js.bat for running dart2js on Windows.

dart/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');
 
 main() {
   List<String> arguments = new Options().arguments;
   Uri cwd = getCurrentDirectory();
   String productDir = appendSlash(nativeToUriPath(arguments[0]));
   String dartVmPath = nativeToUriPath(arguments[1]);
   String productionName = nativeToUriPath(arguments[2]);
   String developerName = nativeToUriPath(arguments[3]);
   String dartDir = appendSlash(nativeToUriPath(arguments[4]));
 
   Uri dartUri = cwd.resolve(dartDir);
   Uri productUri = cwd.resolve(productDir);
 
   Uri dartVmUri = productUri.resolve(dartVmPath);
   Uri productionUri = productUri.resolve(arguments[2]);
   Uri developerUri = productUri.resolve(arguments[3]);
-  String productionScript = buildScript(dartUri, dartVmUri, '');
-  String developerScript = buildScript(dartUri, dartVmUri,
-                                       ' --enable_checked_mode');
+  List<String> productionScript = buildScript(dartUri, dartVmUri, '');
+  List<String> developerScript = buildScript(dartUri, dartVmUri,
+                                             ' --enable_checked_mode');
 
   writeScript(productionUri, productionScript);
   writeScript(developerUri, developerScript);
 }
 
-writeScript(Uri uri, String script) {
+writeScript(Uri uri, List<String> scripts) {
+  String unixScript = scripts[0];
+  String batFile = scripts[1];
   var f = new File(uriPathToNative(uri.path));
   var stream = f.openSync(FileMode.WRITE);
   try {
-    stream.writeStringSync(script);
+    stream.writeStringSync(unixScript);
   } finally {
     stream.closeSync();
   }
 
-  // TODO(ahe): Also make a .bat file for Windows.
+  f = new File('${uriPathToNative(uri.path)}.bat');
+  stream = f.openSync(FileMode.WRITE);
+  try {
+    stream.writeStringSync(batFile);
+  } finally {
+    stream.closeSync();
+  }
 
   if (Platform.operatingSystem() != 'windows') {
     onExit(int exitCode, String stdout, String stderr) {
       if (exitCode != 0) {
         print(stdout);
         print(stderr);
         exit(exitCode);
       }
     }
     new Process.run('/bin/chmod', ['+x', uri.path], null, onExit);
   }
 }
 
-buildScript(Uri dartUri, Uri dartVmLocation, String options) {
+List<String> buildScript(Uri dartUri, Uri dartVmLocation, String options) {
   Uri dart2jsUri = dartUri.resolve('lib/compiler/implementation/dart2js.dart');
   String dart2jsPath = relativize(dartVmLocation, dart2jsUri);
   String libraryRoot = relativize(dartVmLocation, dartUri);
   libraryRoot = uriPathToNative('/../$libraryRoot');
 
   print('dartUri = $dartUri');
   print('dartVmLocation = $dartVmLocation');
   print('dart2jsUri = $dart2jsUri');
   print('dart2jsPath = $dart2jsPath');
   print('libraryRoot = $libraryRoot');
 
-  return """
+  return [
+"""
 #!${dartVmLocation.path}$options
 // 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('$dart2jsPath');
 
 void main() {
   try {
     String libraryRoot = @'$libraryRoot';
     String script = new Options().script;
     List<String> argv = ['--library-root=\$script\$libraryRoot'];
     argv.addAll(new Options().arguments);
     compile(argv);
   } catch (var exception, var trace) {
     try {
       print('Internal error: \$exception');
     } catch (var ignored) {
       print('Internal error: error while printing exception');
     }
     try {
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }
-""";
+""",
+'''
+@echo off
+REM Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+REM for details. All rights reserved. Use of this source code is governed by a
+REM BSD-style license that can be found in the LICENSE file.
+
+set SCRIPTPATH=%~dp0
+
+REM Does the path have a trailing slash? If so, remove it.
+if %SCRIPTPATH:~-1%==\ set SCRIPTPATH=%SCRIPTPATH:~0,-1%
+
+set arguments=%*
+
+"%SCRIPTPATH%\dart.exe"$options "%SCRIPTPATH%\dart2js" %arguments%
+'''.replaceAll('\n', '\r\n')];
 }