anchor.diff:  // - Copy the packages/ directory in build/chrome-app/spark/packages
   // - Remove test
   // - Zip the content of build/chrome-app-spark to dist/spark.zip
  -void archive(GrinderContext context) {
  -  String sparkZip = '${DIST_DIR.path}/spark.zip';
  +void archive(GrinderContext context, [String outputZip]) {
  +  String sparkZip = outputZip == null ? '${DIST_DIR.path}/spark.zip' :
  +                                        '${DIST_DIR.path}/${outputZip}';
     _delete(sparkZip);
     _zip(context, 'app', '../${sparkZip}');
     _printSize(context, getFile(sparkZip));
  
positive.code: // archive and name the archive with the revision identifier.
  void _archiveWithRevision(GrinderContext context) {
    context.log('Performing archive instead.');
    archive(context);
    File file = new File('dist/spark.zip');
    String version = _getCurrentRevision();
    String filename = 'spark-rev-${version}.zip';
    file.rename('dist/${filename}');
    context.log("Created ${filename}");
  }
  
  
negative.code: 
  // Returns the name of the current branch.
  String _getBranchName() {
    return _getCommandOutput('git rev-parse --abbrev-ref HEAD');
  }
  
  // Returns the URL of the git repository.
  