[fsp] Add support for reading directories.

chrome/test/data/extensions/api_test/file_system_provider/get_metadata/test.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 'use strict';
 
 var fileSystemId;
 var fileSystem;
 
 /**
@@ skipping 18 matching lines @@
   modificationTime: new Date(2014, 4, 28, 10, 39, 15)
 });
 
 /**
  * Returns metadata for a requested entry.
  *
  * @param {number} inFileSystemId ID of the file system.
  * @param {string} entryPath Path of the requested entry.
  * @param {function(Object)} onSuccess Success callback with metadata passed
  *     an argument.
- * @param {function(string}} onError Error callback with an error code.
+ * @param {function(string)} onError Error callback with an error code.
  */
 function onGetMetadataRequested(
     inFileSystemId, entryPath, onSuccess, onError) {
   if (inFileSystemId != fileSystemId) {
     onError('SECURITY_ERROR');  // enum ProviderError.
     return;
   }
 
   if (entryPath == '/') {
     onSuccess(TESTING_ROOT);
@@ skipping 107 matching lines @@
           function(error) {
             chrome.test.assertEq('TypeMismatchError', error.name);
             onSuccess();
           });
     }
   ]);
 }
 
 // Setup and run all of the test cases.
 setUp(runTests);