code: function build(TaskConfig, crx) {
      return new Promise(function(resolve, reject){
  	mkdir(path.dirname(TaskConfig.dest), function(err){
  	  if (err) {
  	    return reject(err);
  	  }
  
  	  resolve();
  	});
        })
        .then(function(){
  	return crx.load(TaskConfig.src);
        })
        .then(function(){
  	return crx.loadContents();
        })
        .then(function(archiveBuffer){
  	if (path.extname(TaskConfig.dest) === '.zip') {
  	  grunt.file.write(TaskConfig.dest, archiveBuffer);
  	  grunt.log.ok(TaskConfig.dest + ' has been created.');
  	}
  
  	return archiveBuffer;
        })
        .then(function writeCrxArchive(archiveBuffer){
  	if (path.extname(TaskConfig.dest) === '.crx') {
  	  return crx.pack(archiveBuffer).then(function(crxBuffer) {
  	    grunt.file.write(TaskConfig.dest, crxBuffer);
  	    grunt.log.ok(TaskConfig.dest + ' has been created.');
  	  }).catch(grunt.log.error);
  	}
        });
    }
docs: Builds a pre-configured chrome extension in 3 steps
  
  @api
  @param {crx} WebExtension
  @return null