add source maps support, fixes #50

lib/devc.dart

 // Copyright (c) 2015, 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.
 
 /// Command line tool to run the checker on a Dart program.
 library ddc.devc;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
@@ skipping 100 matching lines @@
   var codeChecker = new CodeChecker(rules, reporter, options);
   var generators = <CodeGenerator>[];
   if (options.dumpSrcDir != null) {
     generators
         .add(new EmptyDartGenerator(options.dumpSrcDir, uri, rules, options));
   }
   var outputDir = options.outputDir;
   if (outputDir != null) {
     var cg = options.outputDart
         ? new DartGenerator(outputDir, uri, rules, options)
-        : new JSGenerator(outputDir, uri, rules);
+        : new JSGenerator(outputDir, uri, rules, options);
     generators.add(cg);
   }
 
   bool failure = false;
   var rootSource = resolver.findSource(uri);
   // TODO(sigmund): switch to use synchronous codegen?
   for (var source in reachableSources(rootSource, resolver.context)) {
     var entryUnit = resolver.context.resolveCompilationUnit2(source, source);
     var lib = entryUnit.element.enclosingElement;
     if (!options.checkSdk && lib.isInSdk) continue;
@@ skipping 31 matching lines @@
     if (options.dumpInfoFile != null) {
       new File(options.dumpInfoFile)
           .writeAsStringSync(JSON.encode(reporter.result.toJsonMap()));
     }
   }
   return new CheckerResults(libraries, rules, failure || options.forceCompile);
 }
 
 final _log = new Logger('ddc');
 final _earlyErrorResult = new CheckerResults(const [], null, true);