Reland 30137 - Fix version generation for dart2js

utils/compiler/create_snapshot.dart

 // Copyright (c) 2013, 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';
 
 Future<String> getVersion(var rootPath) {
   var suffix = Platform.operatingSystem == 'windows' ? '.exe' : '';
   var printVersionScript = rootPath.resolve("tools/print_version.py");
   return Process.run("python$suffix",
@@ skipping 24 matching lines @@
   } else if (tool == "dartdoc") {
     dartdocMain.main(arguments.skip(1).toList());
   }
 }
 
 """;
     return snapshotGenerationText;
   });
 }
 
+Future<String> getDart2jsSnapshotGenerationFile(var args, var rootPath) {
+  var dart2js = rootPath.resolve(args["dart2js_main"]);
+  return getVersion(rootPath).then((version) {
+    var snapshotGenerationText =
+"""
+import '${dart2js.toFilePath(windows: false)}' as dart2jsMain;
+
+void main(List<String> arguments) {
+  dart2jsMain.BUILD_ID = "$version";
+  dart2jsMain.main(arguments);
+}
+""";
+    return snapshotGenerationText;
+  });
+}
+
 void writeSnapshotFile(var path, var content) {
     File file = new File(path);
     var writer = file.openSync(mode: FileMode.WRITE);
     writer.writeStringSync(content);
     writer.close();
 }
 
 Future createSnapshot(var dart_file, var packageRoot) {
   return Process.run(Platform.executable,
                      ["--package-root=$packageRoot",
@@ skipping 29 matching lines @@
   if (!args.containsKey("package_root")) throw "Please specify package_root";
 
   var scriptFile = Uri.base.resolveUri(Platform.script);
   var path = scriptFile.resolve(".");
   var rootPath = path.resolve("../..");
   getSnapshotGenerationFile(args, rootPath).then((result) {
     var wrapper = "${args['output_dir']}/utils_wrapper.dart";
     writeSnapshotFile(wrapper, result);
     createSnapshot(wrapper, args["package_root"]);
   });
+
+  getDart2jsSnapshotGenerationFile(args, rootPath).then((result) {
+    var wrapper = "${args['output_dir']}/dart2js.dart";
+    writeSnapshotFile(wrapper, result);
+    createSnapshot(wrapper, args["package_root"]);
+  });
+
 }